Compare the same home renovation scope before comparing prices
This calculator helps homeowners and family members compare two or three actual written renovation quotations for one home.
A low headline price may exclude demolition, waste removal, preparation, specified materials or finishing work that another contractor has included.
Start with the work, quantities and product specifications you require, then match each contractor's included scope against that common list.
The result separates confirmed costs from conditional amounts and identifies questions to send back for revised written quotations.
A tool for actual quotations, using Korean VAT context
All money is in KRW, and the VAT comparison uses the Korean standard taxable rate where its application has been confirmed.
The calculator does not generate market unit prices or a recommended price per unit of floor area.
For an early budget, start with the interior cost calculator, then return here when you have itemized contractor quotations.
The editable example is fictional and is not a statement of current market prices.
Documents to prepare
- Your required work by room or trade, measured quantities and quantity units
- Each contractor's itemized written quote, package contents and excluded work
- Material manufacturer, model, dimensions and finishing or preparation requirements
- Written additional-work rates, billing units, conversion factors and rounding conditions
- VAT inclusion, actual deposit and progress-payment amounts, and payment dates
When a verbal explanation differs from the document, record the confirmed written terms and keep the difference in the clarification list.
Do not fill a missing price with a different contractor's rate.
Leaving an unconfirmed item unknown keeps that uncertainty visible in the overall comparison.
Define required quantities and material specifications
Required quantity and unit
Separate the work into useful rows such as living-room flooring, bedroom wallpaper and bathroom demolition.
Enter the total quantity you require using the measured area, length, item count or complete-set unit that the quote actually uses.
Installed flooring area, apartment supply area and wall surface area are different measurements.
You can define up to 20 common scope rows, each with a quantity greater than zero.
Product, model and included work
A generic label such as engineered flooring or premium wallpaper does not establish that two products are equivalent.
Record the model, thickness, color and relevant preparation or finishing details.
Mark the contractor's offered specification as matching, different or unknown after checking it against the requirement.
Matching status requires written confirmation; the calculator does not assess material quality.
Count a package price once and link its components
If demolition and flooring are priced as a package, create one package charge and link both scope rows to that package.
Do not add a separate base charge to a component already included in the package.
The original quotation is the sum of package charges plus separately charged standalone work rows.
A package relationship does not remove the need to check each component's included quantity and specification.
A KRW 5,000,000 demolition and flooring package
Enter KRW 5,000,000 once as the package amount and link the demolition and flooring rows to it.
Adding the full package amount again to each component would overstate the quote.
Fix missing package references, unused packages and duplicate entries before comparing the result.
If the package only includes 50 square meters of flooring, counting its price correctly still does not fulfill a requirement for 60 square meters.
Calculate quantity deficits and additional billing units
Deficit = max(0, required quantity − included quantity)
Additional billing units = deficit ÷ required-unit quantity per billing unit
Confirmed addition = confirmed billing units × written additional-work rate
Excess included quantity can be identified, but the calculator does not reduce a quoted contract amount automatically.
Confirm whether billing uses the exact quantity or rounds up to whole packs, rolls or sets.
For a 10-square-meter deficit and a billing unit covering 3 square meters, round-up billing requires 4 billing units.
At a written rate of KRW 50,000 per billing unit, the addition is KRW 200,000.
That is a different agreement from a rate of KRW 50,000 per square meter.
An addition enters confirmed cost only when both the unit conversion and the written rate are confirmed.
Otherwise, retain an explicit user-supplied low and high estimate or leave the addition unknown.
A documented free addition with a zero rate is different from a missing rate.
Normalize VAT and keep conditional additions separate
One VAT basis per contractor
The comparison uses 10% VAT for quotations confirmed to use the Korean standard taxable treatment.
VAT-inclusive inputs are already cash amounts, while VAT-exclusive inputs are multiplied by 1.1.
Included VAT is separated as the total minus the total divided by 1.1, with money rounded to whole won.
Leave the VAT basis unknown if either tax applicability or inclusion is unclear.
Other conditional work
Unconfirmed work such as substrate repairs can remain a user-supplied low and high amount.
Do not include a quantity-deficit addition again in the separate other-additions range.
Enter zero for both bounds only when no such addition has been confirmed.
Replacing an unknown upper cost with zero can understate the cash you need.
For a contractor, package charges, standalone amounts, deficit additions and conditional amounts must all use the selected VAT basis.
Ask for a consistent written breakdown if the quote mixes inclusive and exclusive rows.
This calculator does not determine tax exemption, simplified-taxpayer liability, tax-invoice eligibility, input-tax deductions or refunds.
Worked example: actual-quote structure for contractors A and B
Assume the same home requires one demolition set, 60 square meters of flooring and 120 square meters of wallpaper work.
Specifications and unit conversions have been confirmed for both contractors.
These fictional amounts explain the calculation and are not market benchmarks or recommended unit prices.
Contractor A: VAT-inclusive quotation
- Demolition and flooring package KRW 5,000,000 + wallpaper KRW 2,400,000 = original quote KRW 7,400,000
- Only 50 square meters of flooring are included: the 10-square-meter deficit × written rate KRW 50,000 = confirmed addition KRW 500,000
- Confirmed cost subtotal: KRW 7,900,000
- Separate conditional work: KRW 200,000–600,000 → conditional total KRW 8,100,000–8,500,000
Contractor B: VAT-exclusive quotation
- Demolition KRW 1,000,000 + flooring KRW 4,000,000 + wallpaper KRW 2,600,000 = supply amount KRW 7,600,000
- VAT KRW 760,000 → cash total KRW 8,360,000
- All required quantities are included, with other conditional additions confirmed as zero to zero
- A's KRW 8,100,000–8,500,000 range overlaps B's KRW 8,360,000 total, so the overall lowest-cost decision remains pending
A's confirmed subtotal of KRW 7,900,000 does not establish that A will always be cheaper.
If A's other additions are later confirmed as zero, A's KRW 7,900,000 is below B's KRW 8,360,000.
If A's flooring rate is missing and only a KRW 300,000–700,000 completion estimate is supplied, a conditional cost range may be shown, but scope fulfillment remains pending.
Read confirmed subtotals, conditional ranges and pending results
Confirmed cost subtotal
This combines the original quotation with quantity-deficit additions supported by confirmed billing units and written rates.
If unknown costs remain, it is a subtotal of known items rather than the final completion cost.
An unknown VAT basis also prevents a confirmed cash-equivalent total.
Conditional total and known lower amount
A complete conditional range requires valid low and high bounds for every conditional addition.
If any bound remains unknown, the calculator distinguishes the known lower amount from an incomplete overall range.
A user estimate is not a contractor's contractual maximum price.
A quote is shown as lower across the entire entered range only if all contractors have confirmed scope and VAT, complete cost ranges, and that quote's upper amount is strictly below every other quote's lower amount.
Overlapping ranges, equal amounts and unresolved conditions keep the overall ranking pending.
Prices for different specifications are not treated as the same work, and the result does not rank workmanship or recommend a contract.
Check dated cash payments against the original quotation
Enter the actual planned date and VAT-inclusive cash amount for each deposit, progress payment and final balance.
Payments on the same date are grouped and accumulated in date order, showing original-quote cash due by that point.
The payment schedule is checked against the VAT-inclusive original quote before deficit additions.
Original quote minus scheduled payments is the allocation difference: positive means unallocated money, while negative means over-allocation.
A reconciled original schedule does not fund the additions
Two A payments of KRW 3,700,000 reconcile to the original KRW 7,400,000 quote.
The KRW 500,000 confirmed addition and KRW 200,000–600,000 conditional work still need separate payment-date confirmation.
Two B payments of KRW 4,180,000 reconcile to its VAT-inclusive original total of KRW 8,360,000.
Missing dates are not replaced with invented milestones, deposit percentages or payment dates.
Step-by-step workflow and written revision requests
- Define the common required work, quantities, units and material specifications for one home.
- Match two or three contractors' VAT basis, package charges and standalone amounts to their documents.
- Enter included quantities and offered products, then mark written specification and unit-conversion confirmation.
- Add confirmed deficit rates or conditional bounds, plus separate other additions without duplication.
- Enter actual payment dates and amounts, and reconcile any unallocated or over-allocated difference.
- Copy the clarification list, send it to each contractor and compare revised written quotations for the same scope.
If measurements or material choices change, update the common requirements and every contractor's corresponding rows.
Check whether owner-purchased materials are included in or excluded from each quotation.
Record verbal change requests in writing with the scope, amount and payment timing before relying on them in the comparison.
Practical situations and limits
Reviewing quotes for a family member
Ask for quantities, product names and exclusions rather than only a headline total.
A written clarification list can expose differences between what a homeowner expects and what the contractor priced.
Keep the quotation date and revision number so that terms from different versions do not become mixed.
Additional work after demolition
Distinguish preparation already included in the original scope from newly discovered work.
Confirm new rates and quantities in a written breakdown, and remove any duplicated conditional allowance.
Agreement to change the contract and the timing of the new payments still require separate confirmation.
The result does not determine structural safety, permits, apartment management rules, electrical or fire compliance, contractor capability, defect liability or delay damages.
A conditional upper estimate does not guarantee a maximum actual cost.
Seek the relevant professional and contracting parties' confirmation when site conditions or contractual risks remain unresolved.
Frequently asked questions
Can I compare only the headline totals?
The main purpose is to compare required and included quantities and specifications.
Ask for itemized written quotes because totals alone cannot reveal excluded work or different package contents.
Are area and package units converted automatically?
Actual billing units and conversion factors require contractor confirmation.
Material pack sizes and area definitions can differ, so mark the conversion confirmation explicitly.
What happens when a deficit has no written unit rate?
The missing rate is not replaced with zero.
A user-supplied completion range may be shown with scope fulfillment still pending; without that range, the overall upper cost remains unknown.
Can a cheaper quote with different materials be ranked first?
Different specifications prevent a same-scope lowest-cost decision.
Agree on revised common requirements and ask every contractor to quote those same conditions.
How do I enter work inside a package?
Enter the package price once and link its included scope rows.
Do not add component base charges again, but check each component quantity and specification separately.
Which quote wins when conditional ranges overlap?
The complete range does not establish a lower-cost option.
Confirm the uncertain work and narrow the ranges before making a cost comparison.
Does a reconciled payment schedule include additional work?
The schedule reconciles to the VAT-inclusive original quotation.
Confirm dates for quantity-completion and conditional additions separately; they are not distributed across the original dates automatically.
Does the 10% VAT rate determine tax treatment for every renovation?
It is the comparison basis for confirmed standard taxable quotations.
Tax exemption, simplified-taxpayer liability, invoices, deductions and refunds are not determined; retain unknown VAT status when applicability is unclear.
Official sources and the 2026 reference date
Sources were checked on November 12, 2026.
The 10% standard VAT rate in Article 30 of Korea's Value-Added Tax Act was verified directly through the National Law Information OPEN API.
The current response identified law ID 001571, MST 276117, promulgation on October 1, 2025, and an effective date of January 2, 2026 for both the act and the cited article.
- National Law Information OPEN API: Article 30 — standard taxable VAT basis for the quotation comparison
- Published interior construction and window-work standard contract — Standard Terms No. 10079, initial edition dated March 21, 2018
- Korea Ministry of Government Legislation: home repair dispute guidance — guidance dated October 15, 2026 on detailed written quotations
Article 3 of the published standard contract provides a reference structure for VAT-inclusive contract amounts, payment dates and itemized scope, quantities, products and specifications; Article 8 addresses changes to the work.
The verified 2018 initial edition is not asserted to be the latest revision or a statutory formula automatically governing every contract.
Recheck later amendments, the actual quotation's tax basis and the terms agreed by the parties before signing.
Request the missing scope in a revised written quote
First check that the quote includes the quantities and specifications you need.
Match the actual documents in the calculator, copy the unresolved items and payment differences, and send them to each contractor.
Use the revised quotations to compare the same work, VAT basis and additional-cost conditions again.
Check an early renovation budget