Korea G-SEED Certification Fee & Payback Calculator
Calculate current Korean G-SEED preliminary, final, and extension fees with 2026 labour rates, then evaluate total project cost, payback, NPV, and ROI.
Labour rates use the 2026 official workbook preset checked 2026-08-11; project costs and benefits are a fictional worked example.
1. Certification route and building
The route and building type select the regular formula, existing-building adjustment, or fixed fee.
m²
Used for scale interpolation and detached-house fixed-fee bands.
uses
Two uses add 0.1; three or more add 0.2.
people
Final-review allowance; it is not added to fixed-fee building types.
2. 2026 labour rates and expenses
Labour presets are editable; enter actual pre-VAT travel and nameplate quotes.
KRW/day
2026 official workbook preset
KRW/day
2026 official workbook preset
KRW/day
2026 official workbook preset
KRW
Enter the actual pre-VAT quote.
3. Project initial and upkeep cost
Combine external quotes and internal economic cost without duplicating the official fee.
KRW
Use an itemised proposal or internal budget.
KRW
Non-overlapping energy, daylight, LCA, and evidence cost
KRW
Testing, measurement, and performance-verification quote
KRW
Enter only the increment above the baseline design.
hours
Evidence collection, design coordination, and review support
KRW/hour
Employer cost or documented opportunity value
KRW
Cost not duplicated in another field
KRW
Enter only awarded, non-repayable support.
KRW/year
Incremental monitoring, evidence, training, and operation cost
4. Incremental benefits and timing
Utility and operating savings are included in full; certification-dependent contribution is probability-weighted.
KRW/year
Use verified savings against a documented baseline.
KRW/year
Non-overlapping maintenance and operating savings
KRW/year
Include only incremental opportunities that genuinely require G-SEED.
%
Probability applies only to certification-dependent contribution.
months
Planned time from assessment to certification
months
Zero starts benefits in the first month after certification.
months
12 to 240 months
months
Measured after certification and no longer than the horizon.
%
Hurdle rate or cost of capital
G-SEED fee and payback results
Official fee for selected route
KRW 20,702,000
Supply KRW 18,820,000 · VAT KRW 1,882,000
Net initial economic cost
KRW 320,702,000
External net cash KRW 280,702,000 · includes internal effort
Sustained payback
66.7 months
Includes 18 preparation months · 48.7 months after certification
NPV
KRW 303,171,471
Discounted payback 72.4 months · ROI 123.27%
Official fee calculation
Applied scale coefficient 0.9 · each stage is floored to KRW 10,000
Official fee detail by certification stage
Stage
A
B
C
D
Supply
With VAT
Preliminary
KRW 6,785,247
KRW 678,525
KRW 678,525
KRW 0
KRW 7,320,000
KRW 8,052,000
Final
KRW 9,772,392
KRW 977,239
KRW 977,239
KRW 950,000
KRW 11,500,000
KRW 12,650,000
The current extension-fee reference is KRW 1,480,000 supply and KRW 1,628,000 with VAT.
Economic decision metrics
Annual expected benefit
KRW 85,000,000
Annual net benefit
KRW 79,000,000
First payback
48.7 months
Discounted payback
54.4 months
Horizon total benefit
KRW 850,000,000
Horizon total cost
KRW 380,702,000
Nominal net value
KRW 469,298,000
Required dependent contribution for 60-month target
KRW 280,800
Annual cash flow
Expected benefit, upkeep, extension cost, and cumulative cash flow by year
Year
Benefit
Upkeep
Extension
Net cash
Cumulative
1
KRW 85,000,000
KRW 6,000,000
KRW 0
KRW 79,000,000
-KRW 241,702,000
2
KRW 85,000,000
KRW 6,000,000
KRW 0
KRW 79,000,000
-KRW 162,702,000
3
KRW 85,000,000
KRW 6,000,000
KRW 0
KRW 79,000,000
-KRW 83,702,000
4
KRW 85,000,000
KRW 6,000,000
KRW 0
KRW 79,000,000
-KRW 4,702,000
5
KRW 85,000,000
KRW 6,000,000
KRW 0
KRW 79,000,000
KRW 74,298,000
6
KRW 85,000,000
KRW 6,000,000
KRW 0
KRW 79,000,000
KRW 153,298,000
7
KRW 85,000,000
KRW 6,000,000
KRW 0
KRW 79,000,000
KRW 232,298,000
8
KRW 85,000,000
KRW 6,000,000
KRW 0
KRW 79,000,000
KRW 311,298,000
9
KRW 85,000,000
KRW 6,000,000
KRW 0
KRW 79,000,000
KRW 390,298,000
10
KRW 85,000,000
KRW 6,000,000
KRW 0
KRW 79,000,000
KRW 469,298,000
Assumptions to verify
Fees use the 2026 labour preset and your expenses. Confirm the application-date G-SEED workbook and a written certification-body quote.
G-SEED does not automatically guarantee utility, rent, contract, or financing benefits. Validate each assumption with baselines, contract terms, and measurements.
G-SEED cost is much broader than the certification-body fee
The Korean Green Standard for Energy and Environmental Design evaluates land use, energy, water, materials, indoor environment, and building management. A project budget often starts with the certification-body review fee, but a defensible investment case also needs design coordination, self-assessment documents, energy and daylight simulations, life-cycle evidence, commissioning, tests, incremental construction, and internal review effort. Those costs can be materially larger than the statutory review fee.
Certification also does not automatically create utility savings, rent premiums, contract awards, or financing improvements. This calculator keeps the official fee formula separate from project-specific cost and then evaluates only documented incremental benefit. It is designed for budgeting and decision support, not for determining legal obligation, certification grade, score, tax treatment, or the final amount invoiced by a certification body.
What this calculator models
Current official fee logic
Preliminary, final, combined, and validity-extension routes use the current labour composition, technical expense, indirect expense, scale coefficient, deliberation allowance, actual expense, rounding, and VAT rules.
Building-specific branches
Multi-family residential projects use the lower area or household coefficient. Non-residential projects apply an area coefficient and mixed-use addition. Detached houses and green-remodeling projects use fixed fees.
Full incremental investment
Consulting and design support, simulations, evidence, commissioning, tests, incremental green upgrades, internal effort, other direct cost, grants, and annual upkeep are kept as separate inputs.
Evidence-based benefits
Verified utility and operating savings are included in full. Contribution available only because G-SEED is required is probability-weighted to reflect uncertainty.
Monthly decision metrics
The model reports first, sustained, and discounted payback, calendar payback including preparation, nominal value, NPV, ROI, annual cash flow, and the contribution required to hit a target month.
Long-term extension scenario
Users can place a current-cost extension estimate before the ten-year final-certificate expiry and every five years thereafter, with an explicit warning that future rates may change.
Check the legal scope before estimating the fee
Article 16 of the Green Buildings Construction Support Act establishes the certification system, application route, and authority to collect fees. Article 11-3 of its Enforcement Decree defines a mandatory-certification boundary for certain public buildings. The ownership or management body, whether the work is new construction, reconstruction, or a separate extension, total floor area of at least 3,000 square metres, and whether an energy-saving plan must be submitted all matter. Floor area alone is not a legal determination.
A private development may still face a G-SEED requirement through a local ordinance, planning incentive, public tender, financing covenant, investor standard, or tenant condition. Confirm the exact application boundary, building classification, target grade, and any incentive requirement with the architect, competent authority, and selected certification body. The calculator estimates a route after those facts are selected; it does not decide which route is legally required.
Preliminary certification, final certification, and validity extension
Purpose, validity boundary, and main budget driver for each G-SEED route
Route
Review basis
Validity boundary
Main fee drivers
Preliminary
Performance represented in design documents
Use approval, use inspection, or earlier final certificate
Completion documents, site inspection, deliberation
Ten years from issue
Document and site labour, travel, member allowances
Extension
Continued performance and extension evidence
Five years from extension
Reduced labour, travel, certification nameplate
Preliminary certification is a design-stage review and does not replace final certification after completion. A normal final review includes document review, site inspection, and certification deliberation, although deliberation may be omitted for detached houses and green-remodeling projects. An extension application may be made from 180 days before expiry through the expiry date. Long-hold projects should therefore budget not only for a future invoice but also for maintaining evidence and operating records before that filing window.
The 2026 A, B, C, and D fee formula
The current general formula begins with labour item A. Item B is technical expense equal to 10 percent of the original A, and item C is indirect expense equal to another 10 percent of the original A. Item D contains actual expenses and deliberation allowances that are added after the scale coefficient. Each selected certification stage is floored to a KRW 10,000 unit before 10 percent VAT is calculated.
The default daily rates are taken from the G-SEED 2026 official review-fee workbook checked on 11 August 2026: KRW 467,217 for a professional engineer, KRW 373,353 for a special engineer, and KRW 310,884 for a senior engineer. The notice requires revised labour rates to be used when the underlying rate basis changes, so these fields remain editable. Replace all three with the application-date workbook if a newer version is published.
Preliminary review labour A
The base composition is two professional engineers for three days, three special engineers for three days, and two senior engineers for ten days at an administrative factor of 0.1. Issuing a housing-performance grade certificate together changes the special-engineer count to 3.4 and the administrative factor to 0.14. When preliminary deliberation is held, one senior-engineer day and KRW 150,000 per member are added.
Final review labour A
Document review uses two professional engineers for three days and three special engineers for three days. Site review adds two professional engineers for one day and three special engineers for one day. Administration adds two senior engineers for ten days at 0.2, and deliberation adds one senior-engineer day. Item D adds actual travel and KRW 150,000 for each deliberation member.
General stage formula
Supply amount = floor to KRW 10,000 [(adjusted A + B + C) × scale coefficient + D] VAT = supply amount × 10% Estimated payment = supply amount + VAT
Residential interpolation and non-residential mixed use
A multi-family residential project calculates an area coefficient and a household coefficient independently, rounds each interpolated value to four decimal places, and uses the lower result. For example, 10,000 square metres lies between 5,500 square metres at 0.5 and 33,000 square metres at 0.7, producing 0.5327. One hundred households lies between 50 at 0.5 and 300 at 0.7, producing 0.54. The applied coefficient is therefore 0.5327.
A non-residential project interpolates only the area table and then adds 0.1 for two recognized uses or 0.2 for three or more. The count must follow the classification accepted by the certification body, not an informal count of tenants or rooms. A complex project should confirm whether separate wings, podium and tower uses, or ancillary areas are treated as one application and how mixed use is counted.
Major G-SEED scale coefficient points for residential and non-residential buildings
Series
Lower band
Selected anchors
Upper boundary
Rule
Residential area
Below 5,500 m²: 0.5
33,000 m²: 0.7; 110,000 m²: 1.0
At least 220,000 m²: 1.4
Linear interpolation within bands
Residential households
Below 50: 0.5
300: 0.7; 1,000: 1.0
At least 2,000: 1.4
Use lower area or household result
Non-residential area
Below 500 m²: 0.5
10,000 m²: 0.9; 100,000 m²: 1.4
At least 1,000,000 m²: 5.0
Interpolate, then add mixed-use factor
The top boundaries contain a step in the published table. At 220,000 square metres or 2,000 households the residential coefficient becomes 1.4, and at 1,000,000 non-residential square metres it becomes 5.0. Values just below those boundaries approach 1.2 or 4.0 respectively. A display-rounding difference near a fee-floor boundary can move the final supply amount by KRW 10,000, so use the current official workbook for an application-ready figure.
Detached-house, green-remodeling, and existing-building rules
Current fixed G-SEED certification supply fees for detached houses and green remodeling
Building type
Area band
Certification or preliminary supply fee
Detached house
Up to 85 m²
KRW 600,000
Detached house
Over 85 m² through 250 m²
KRW 800,000
Detached house
Over 250 m²
KRW 1,200,000
Residential green remodeling
Fixed
KRW 600,000
Non-residential green remodeling
Fixed
KRW 1,200,000
Annex 12 of the current certification notice and the G-SEED fee page show the fixed detached-house amounts above and state that travel and certification-nameplate expense are included in the fixed schedules. Some formula cells in the official 2026 spreadsheet instead return KRW 0.6 million, KRW 1.2 million, and KRW 2.0 million for the three detached-house bands. The calculator follows the binding current notice at KRW 0.6 million, KRW 0.8 million, and KRW 1.2 million and always displays a source-conflict warning. Obtain a written band confirmation before applying.
For a normal existing-building final review, the notice reduces labour item A to 70 percent. Items B and C remain 10 percent each of the original, unadjusted A. Multiplying the entire new-building fee by 70 percent would therefore understate the estimate. The adjustment is not applied again to a detached-house or green-remodeling fixed fee.
Extension formula, VAT, re-review, and refunds
A validity extension uses one professional engineer for one day, one special engineer for one day, and one senior engineer for one day at an administrative factor of 0.2. Technical and indirect expense are each 10 percent of that labour amount. Actual extension travel and certification-nameplate expense are then added before the result is floored to KRW 10,000 and VAT is calculated. With the 2026 default rates and KRW 200,000 for each actual-expense field, the supply amount is KRW 1,480,000 and the amount with VAT is KRW 1,628,000.
Select recoverable VAT only after confirming Korean input-tax treatment. The model then uses the supply amount rather than the tax-inclusive payment as economic investment.
A general re-review fee is 50 percent of the initial certification fee. Detached-house, green-remodeling, and extension re-review uses the applicable initial fee instead. The calculator does not automatically assume a failed or repeated review.
Maintain a separate contingency for scope change, document supplementation, score shortfall, and redesign when those risks are material. Do not hide that contingency inside verified energy savings.
Refund rate by G-SEED application withdrawal stage
Withdrawal stage
Refund rate
Budget implication
After receipt
90%
Receipt is not a full-refund point
After supplementation request
60%
Evidence quality affects loss exposure
After document review
30%
Late design decisions carry high sunk cost
After site inspection
15%
Most review effort is already incurred
After deliberation
0%
No fee refund
Build the complete incremental cost estimate
Freeze a baseline design. Exclude statutory minimum energy performance, ordinary equipment, and design effort that the project needs without G-SEED. Only the difference attributable to the selected certification strategy belongs in incremental investment.
Keep the official fee outside private quotations. Ask whether a consultant proposal includes certification-body payment, simulations, tests, travel, or VAT. Remove duplicated amounts before entering each line.
Separate simulation and evidence packages. Map energy, daylight, acoustics, life-cycle assessment, materials, commissioning, and field tests to a responsible supplier and quote date.
Enter the green-upgrade increment. Use the difference between baseline and proposed equipment or construction, not the full purchase price. Document which credits or measured outcomes each increment supports.
Value internal preparation consistently. Include owner, architect, engineer, contractor, commissioning, procurement, and operation-team hours at an employer-cost or documented opportunity-value basis.
Deduct only confirmed grants. Keep an unawarded subsidy, possible planning incentive, or expected tax benefit out of the base case until eligibility and amount are documented.
Add recurring evidence cost. Annual monitoring, meter review, records, training, maintenance, and performance verification should be incremental to ordinary operation and stated in the same price basis as annual benefit.
Cash outlay versus economic cost
Gross external cost combines the applicable official fee investment amount with consulting, simulations, commissioning, incremental green upgrades, and other direct cost. Confirmed grants reduce that amount with net cash outlay floored at zero. Internal preparation hours multiplied by hourly cost are then added to create initial economic cost, which is the starting balance for payback and NPV. This is a management-decision measure and is not a statutory accounting or tax classification.
Use separate evidence for performance and certification benefits
Utility savings should compare the proposed project with a documented baseline using calibrated simulation, weather-normalized historical consumption for an existing building, or a measurement and verification plan. Operating savings should cover non-overlapping maintenance time, consumables, failures, waste, or service cost. If an efficiency measure would be installed without G-SEED, both its incremental cost and its savings may belong to a broader green-investment case rather than the certification-only case.
Certification-dependent contribution is different. Enter only incremental net contribution from a lease, tender, financing arrangement, investment mandate, or sale condition that genuinely requires the selected G-SEED outcome. Do not enter full revenue. Use contribution after avoidable delivery cost and then apply a probability supported by the commercial pipeline. The model probability-weights only this dependent component; documented utility and operating savings remain separate.
Useful evidence
Baseline-versus-proposed energy-model output
Meter boundary and measurement plan
Lease clause naming a green certification grade
Tender scoring table or eligibility condition
Financing term sheet tied to certification
Opportunity register with probability owner
Assumptions to exclude
General market rent growth unrelated to G-SEED
Existing contracted revenue
Operating savings duplicated in utility savings
Unawarded subsidies or uncertain tax benefits
Unsupported whole-asset value premiums
Benefits beginning before the actual delivery date
How the payback and value metrics work
Expected annual net benefit
Expected certification contribution equals the entered annual dependent contribution multiplied by realization probability. Utility savings and operating savings are added to obtain annual gross benefit. Annual certification upkeep is deducted to obtain annual net benefit. A post-certification delay suppresses benefits for the selected months while annual upkeep continues.
First and sustained payback
First payback is the first point at which nominal cumulative cash flow reaches zero. Sustained payback is the first crossing after which cumulative value never becomes negative again during the selected horizon. The distinction matters when a later extension fee can pull a previously positive project below zero. Calendar payback adds the preparation period to the post-certification result.
Discounted payback, NPV, and ROI
Discounted payback reduces every monthly net flow by the annual hurdle rate raised to the month fraction. NPV is initial economic cost plus all discounted monthly net flows. Nominal ROI divides total undiscounted net value by total cost, so it does not replace NPV when projects have different timing or horizons.
Required contribution for a target month
The reverse calculation totals initial economic cost, upkeep through the target, and any extension event through that month. Guaranteed utility and operating savings over active benefit months are deducted. The remaining amount is divided by active years and realization probability to obtain the annual certification-dependent contribution required to recover by the target. A zero probability or zero active period makes the result unavailable unless guaranteed savings already cover the target cost.
Long-term extension timing
A final certificate is valid for ten years, and an extension is valid for five years. When future extension cost is enabled for a final or combined route, the calculator places the first event in month 115 after certification, approximating the opening of the 180-day filing window, and repeats it every 60 months. When the selected initial route is already an extension, the next event begins in month 55 and repeats every 60 months. Preliminary-only analysis creates no automatic extension because the timing of completion and conversion to final certification is project-specific.
Every future event uses the current extension formula, labour rates, travel expense, nameplate expense, and VAT assumption. That is a constant-price scenario rather than a forecast. Compare a case with extension disabled, a current-price case, and a higher-rate manual scenario if the holding period extends beyond the first expiry. Also budget staff time and performance remediation separately because the official extension fee does not represent all future evidence and improvement cost.
Official-formula worked examples
10,000 m² non-residential building
Assume one use, new-building status, KRW 350,000 final-review travel, and four deliberation members. The scale coefficient is 0.9. At the 2026 default labour rates, preliminary supply is KRW 7,320,000 and final supply is KRW 11,500,000. Combined supply is KRW 18,820,000, and the tax-inclusive estimate is KRW 20,702,000. Changing only the final route to existing-building status produces KRW 8,860,000 of final supply because only A is reduced to 70 percent.
10,000 m² and 100-household residential building
The area coefficient is 0.5327 and the household coefficient is 0.54, so 0.5327 applies. Without the housing-performance option or preliminary deliberation, preliminary supply is KRW 4,330,000. With KRW 350,000 final travel and four final members, final supply is KRW 7,190,000. Combined supply is KRW 11,520,000, VAT is KRW 1,152,000, and the tax-inclusive estimate is KRW 12,672,000.
These figures are deterministic checks of the implementation, not market quotes. Actual results change with workbook rates, recognized floor area and households, mixed-use classification, housing-performance handling, whether preliminary deliberation occurs, member counts, actual travel, and the selected certification body. Preserve a copy of the official workbook and written quote used for an approval memo.
Practical decision scenarios
Design-stage budget gate
A developer can select preliminary plus final certification and compare low, base, and high incremental-construction quotes. Link every upgrade to a score strategy and a measurable operating outcome. If NPV depends entirely on an unsupported asset premium, the team can separate mandatory compliance from elective performance before design development locks in cost.
Existing asset renewal
An asset manager can compare the normal existing-building final formula with a green-remodeling fixed-fee route. The cheaper result is not permission to select that route. Eligibility depends on the work scope and certification definitions, so request a pre-review from the certification body and keep performance-remediation cost outside the small official fee.
Tenant, tender, or financing condition
When a tenant, authority, lender, or investor explicitly names G-SEED, enter only the incremental contribution attached to that condition and a probability owned by the commercial team. Compare the required target contribution with the evidence-backed opportunity pipeline. A large gap signals that scope, schedule, grant strategy, or commercial terms need revision.
Long-hold portfolio plan
A public owner or long-term investor can extend the horizon beyond ten years, enable extension fees, and assign responsibility for meter data, records, and renewal preparation. Use a separate higher-rate scenario because the current workbook cannot predict labour rates at the first or later renewal.
Input checklist and limitations
Match gross floor area to the certification application boundary and confirm how multiple buildings or wings are grouped.
Use the design-document household count for residential projects and confirm whether an unusual accommodation type belongs in the residential route.
Replace default member counts and actual expenses with a written certification-body quote rather than treating the example as a market average.
Update all three labour rates together from the current workbook so preliminary, final, and extension formulas use one consistent basis.
Do not add full equipment cost when the baseline already requires equipment. Enter only the incremental amount attributable to the selected performance strategy.
Align the benefit delay with completion, measurement stabilization, lease commencement, contract delivery, or financing effectiveness.
Compare extension-included and extension-excluded cases for horizons beyond ten years, and state that future prices are uncertain.
Record a quote date, source owner, baseline, evidence file, and approval status for every material input used in an investment memo.
Do not use the output as a certification-grade prediction, score simulation, legal opinion, tax opinion, accounting treatment, or final invoice.
Frequently asked questions
Why can the result differ from a certification-body quote?
The application-date labour rates, workbook version, recognized area and household count, mixed-use classification, housing-performance option, deliberation status, member count, and actual travel expense may differ. The calculator supports budgeting; the written certification-body calculation controls the actual payment.
Does preliminary certification remain valid for ten years?
No. Preliminary certification is a design-stage status that ends at use approval, use inspection, or an earlier final certificate. A completed building still needs the final-certification process and budget. The ten-year period applies to final certification under the current rule.
Why does the detached-house route show a warning?
The current notice and fee page show KRW 0.6 million, KRW 0.8 million, and KRW 1.2 million, while some formula cells in the official 2026 workbook return different amounts. The calculator follows the current notice and tells users to obtain written confirmation before applying.
Should all green-building construction cost be entered?
Use the incremental difference above a documented no-certification baseline. Statutory minimum performance and ordinary project-quality cost belong in the baseline. Internal coordination and ongoing evidence cost should still be included when they are incremental and material.
Is a short payback result enough to approve the project?
First inspect whether the result depends on an unsupported dependent benefit, understated construction scope, recoverable-VAT assumption, or immediate benefit timing. Compare lower realization, delayed benefit, higher cost, and extension-included cases. Approve only when source documents and owners support the assumptions.
Does the calculator estimate the G-SEED score or grade?
No. It models the fee formula and user-supplied economic assumptions. Credit eligibility, weighting, mandatory items, innovation points, grade thresholds, evidence acceptability, and certification outcome require the current technical criteria and professional review.
Official sources and next step
The implementation was checked on 11 August 2026 against the current Green Buildings Construction Support Act, the Green Building Certification Rules, Article 8 and Annex 12 of the Green Building Certification Standard, the G-SEED fee page, and the official 2026 review-fee workbook. Rules, labour rates, actual expenses, and workbooks can change, so recheck the application-date materials before approval or filing.
Export the result into a decision record that links the certification-body quote, design-team increment schedule, baseline energy case, measurement plan, commercial evidence, and a named owner for every assumption. A transparent source trail turns a payback estimate into a reviewable project decision.