Review daylight setbacks before fixing a building design
This calculator compares the assessed height of each building part with its horizontal distance to the due-north plot boundary under Korean rules.
It helps an owner preparing a new building identify parts that may need a larger setback or a lower height before an architectural consultation.
A floor-area estimate alone does not establish that the intended building shape fits the applicable height restrictions.
Enter different distances for individual storeys, recessed upper parts or assessed rooftop parts, then save a review sheet with the assumptions that still need checking.
For a design with lower storeys close to the boundary and upper storeys stepped back, one distance for the entire building is not sufficient.
Each assessed height must be paired with the distance measured from that same part.
The calculator organizes this relationship; it does not establish permit eligibility or calculate actual hours of sunlight.
What to take to your architect
- Required north-side setback for each assessed building part
- Additional distance needed and the height envelope at the entered distance
- Unresolved zoning, ground-datum, local ordinance and exception questions
- A CSV review carrying dimensions, assumptions and evidence together
The 2026 Korean general rule and its scope
Article 61(1) of the Korean Building Act restricts building heights relative to the due-north adjoining plot boundary in exclusive and general residential zones.
Article 86(1) of its Enforcement Decree separates parts at or below 10 m from parts above 10 m and requires the applicable distance to be checked against the local building ordinance.
District plans and special provisions may also matter; an address or a familiar zoning name is not enough to determine the complete rules.
Conditions for this calculation
Both the building site and the due-north adjoining site must be confirmed as exclusive or general residential zones.
This tool covers buildings other than multi-family housing on equal, level ground, with checked assessed heights and due-north horizontal measurements.
It also requires confirmation that no separate special rule or exclusion applies.
Cases that remain pending
Other zones, multi-family housing, sloping or unequal ground, a distance that is not due north, or a potential exception require separate review.
Unknown applicability is not treated as a pass.
Being outside this general rule is also not treated as unlimited building height.
North-adjacent zoning is especially important: Article 86(2)(3) provides an exclusion from paragraph 1 when the due-north adjacent plot is not in an exclusive or general residential zone.
Prepare land-use information for the opposite side of the boundary as well as your own site.
The actual appearance or use of a plot does not necessarily identify its legal zoning.
This is a Korea-specific planning tool, not a substitute for the local authority or an architect reviewing all applicable requirements.
What the height and distance inputs mean
Total assessed height H
H runs from the common ground datum to the top of the part being checked.
It is not the ceiling height or the height of one individual storey.
Three illustrative parts with 3 m increments would therefore have total heights of 3 m, 6 m and 9 m.
For actual drawings, use assessed values checked by the architect, including the treatment of floor levels, structure and rooftop elements.
Due-north horizontal distance D
D runs horizontally due north from the selected part to the adjacent plot boundary.
Do not substitute a visual estimate to a fence or a diagonal shortest distance.
If an upper storey is recessed, enter the distance from that upper part.
An irregular boundary or building outline may require several review points, including the most restrictive locations.
Rows are individual samples and cannot prove that every part of a complex building has been checked.
Ground levels and ordinance evidence
Unequal ground levels require the assessment datum to be reviewed under Article 119 first.
Do not arbitrarily subtract a level difference or add half of a road width.
If the local ordinance has been confirmed to match the national minimum criteria, record the ordinance name, article and check date, or the relevant authority confirmation.
If a different distance or condition applies, the displayed national values must not be used as the final design criteria.
Compare up to 20 parts independently; the tool does not accumulate heights based on row order.
Accepted height inputs are above zero and at most 500 m; distance inputs range from zero to 1,000 m, with up to six decimal places.
These limits describe the tool, not statutory permission for a building of that size.
Leave unknown dimensions blank.
A missing distance differs from an actual distance of zero at the boundary.
Required setback and inverse height formulas
From height to required distance
H ≤ 10 m → R = 1.5 m
H > 10 m → R = H / 2
Additional setback = max(0, R − D)
Exactly 10 m belongs to the lower band.
Above 10 m, half of the entire height of that part is used, not half of the excess above 10 m.
A 12 m part therefore needs a 6 m reference setback.
Do not calculate it by adding half of the excess height to the lower-band 1.5 m distance.
From distance to a height envelope
D < 1.5 m → no positive-height envelope
D ≥ 1.5 m → Hmax = max(10, 2D)
Excess height = max(0, H − Hmax)
At distances from 1.5 m through 5 m, the general-rule envelope for that part is 10 m.
Above 5 m, the envelope increases to twice the distance.
A distance below 1.5 m is reported as having no positive-height envelope under this rule; it is not an approved height of zero.
The inverse formula is a mathematical restatement of the general distance bands.
It does not replace ordinance verification or combine district height controls, coverage limits, floor-area ratios and other building requirements.
Each envelope belongs to the entered distance for one part.
An upper part farther from the boundary cannot establish the acceptable height of a lower part nearer the boundary.
Step-by-step use
- Collect the land information and drawings.
Check zoning on both sides of the boundary, the legal boundary location, due north and the ground datum.
An existing fence alone does not establish the cadastral boundary.
- Select only the conditions that have been checked.
Confirm the building type and possible road, open-space, south-side or other special provisions.
Leave unknown conditions unconfirmed.
Selecting no exception merely to obtain a numeric result creates an unsupported assumption in the saved review.
- Enter a height-distance pair for each part.
Lower-to-upper order is convenient, but rooftop or projecting parts can have separate labels.
Check again that the entered heights are total assessed heights from the datum.
- Read shortfalls and unresolved conditions together.
Compare adding the missing distance with reducing the height at the existing distance.
A layout change may also alter distances for other parts.
Recheck those rows when the design changes.
- Send the CSV with the drawings.
The review includes the source-check date, applicability assumptions and ordinance memo.
Ask the architect to verify local rules, boundary and height assessment, special provisions and other requirements before the design is finalized.
Worked examples: the 10 m boundary and an upper setback
These fictional examples assume equal, level ground and the general applicability conditions.
They show the national minimum reference, not a local ordinance decision or a finding about your land.
The fourth part in the example button has H = 12 m and D = 4 m.
Its required setback is 6 m, leaving a 2 m shortfall.
At the existing distance, the height envelope is 10 m and the excess height is 2 m.
National reference examples for height, setback, required distance and height envelope; all values in metres| Case | H / D | Required D | Extra D | Max H |
|---|
| Exactly 10 m | 10 / 1.5 | 1.5 | 0 | 10 |
| Just above 10 m | 10.000001 / 1.5 | 5.0000005 | 3.5000005 | 10 |
| Before upper setback | 12 / 4 | 6 | 2 | 10 |
| After upper setback | 12 / 6 | 6 | 0 | 12 |
| Higher part | 15 / 6 | 7.5 | 1.5 | 12 |
A part at D = 1.499999 m misses the 1.5 m minimum even when H is only 6 m.
Rounding before the comparison could hide this boundary difference, so the calculation uses unrounded input values.
These very small differences illustrate the legal bands; they are not construction tolerances or a reason to omit practical design margins.
Read the status and diagram correctly
Confirm applicability
Numeric review remains pending if zoning, direction, ground levels, building type, assessed heights or exceptions do not meet the supported assumptions.
This is not a refusal of permission.
It means facts needed for this general calculation must be established first.
Likewise, a potential exclusion is not automatically treated as an exemption.
National reference or checked general-rule comparison
If the other assumptions are confirmed but the ordinance is unknown, results remain national-minimum references.
Confirming the same local criteria and recording evidence changes the status to a checked general-rule comparison.
In either case, within reference describes a numeric comparison for the entered part, not approval of the building.
The blue area in the diagram shows the general-rule envelope on distance and height axes.
The star identifies the selected part, while the table provides its exact dimensions.
The graphic does not model sunlight by time of day, surrounding shadows, seasonal variation or blocked views.
When the reviewed count is smaller than the total row count, complete the missing dimensions before treating the review of the entered parts as finished.
Practical consultation scenarios
Before buying land
List intended storeys and approximate total heights, then compare them with north-side distances.
A large shortfall is a reason to discuss feasible layouts with an architect before committing to a purchase.
Consider actual design feasibility alongside an advertised floor-area estimate.
Comparing an upper-storey recess
For a 12 m part, changing D from 4 m to 6 m reduces the national-reference shortfall from 2 m to zero.
The lost floor area, circulation and structural implications require a separate design comparison.
Save each alternative with a different CSV filename so the consultation can identify the dimensions changed between versions.
Checking rooftop and projecting parts
Entering only the highest occupied storey may omit other relevant parts.
Have the inclusion and assessed height of rooftop elements confirmed before adding separate rows.
Do not exclude every parapet or rooftop structure as a group.
A jointly owned family site
Use the same drawings and inputs when co-owners have different expectations for height and floor area.
Keep unresolved ordinance or exception questions beside the numeric results.
The review supports discussion but does not resolve ownership, boundary disputes or consent from adjoining owners.
Exceptions and limits that are not applied automatically
- Multi-family housing: Article 61(2) and Decree Article 86(3) involve additional daylight-window and building-spacing rules, so this calculator keeps the review pending.
- Roads and open spaces: Article 86(6)–(7) may change how a boundary is treated depending on the facility and building type.
The tool does not automatically add the whole or half of a road width.
- South-side and low-rise provisions: Article 61(3) covers special south-side rules, while Article 61(4) permits ordinance-based exclusions for buildings of at most two storeys and no more than 8 m.
Being a small building does not establish a nationwide exemption.
- Unequal ground and excluded heights: Article 119 governs assessment datums and rooftop-height treatment.
Pilotis storey height is not automatically deducted from the due-north Article 61(1) check.
- Other regulations and civil claims: Building lines, open space within a plot, parking, structure, floor-area ratio, coverage and civil sunlight-loss compensation are not resolved by this distance comparison.
Building-rule assessment and actual harm assessment serve different purposes.
An existing permit or an older design may require the law and transitional provisions applicable at that time.
The calculator uses the current 2026 general rule and does not switch automatically to a historical rule set.
Ask the architect about suitable measurement, design and construction margins instead of relying on rounded numbers that appear exactly on a limit.
Frequently asked questions
What distance is required at exactly 10 m?
The national minimum reference is 1.5 m.
Once a part exceeds 10 m, half of its entire assessed height is used.
The local ordinance and the height assessment still need checking.
At 12 m, do I divide only the excess 2 m by two?
No.
The general required distance for a 12 m part is 12 divided by two, or 6 m.
The formula does not add half of the excess height to the lower-band 1.5 m setback.
Is the height envelope 8 m when the distance is 4 m?
Under the general inverse rule it is 10 m.
Parts at or below 10 m use the 1.5 m minimum, so simply doubling the distance for every height would give the wrong answer.
Can I use the calculator before checking the ordinance?
Yes, as a national-minimum reference if the other applicability conditions are confirmed.
Different local requirements need separate review.
Do not select the same criteria without checking them.
Does it calculate sunlight hours or compensation?
No.
It compares general height and distance rules.
Sunlight duration, civil tolerability, property-value loss and damages require separate assessment.
The sunlight-loss compensation calculator has a different purpose.
Can I add a road on the north side to my distance?
First check boundary treatment, building type and the other conditions under Article 86.
Do not arbitrarily add half or all of the road width.
Mark a possible exception and ask an architect.
Can I build if every row is within reference?
The result only means the entered parts meet the selected general numeric comparison.
Omitted parts, local rules, other height controls, structure, parking and permit requirements still need review by the architect and authority.
Does not assessed in the saved sheet mean zero?
No.
It identifies a missing dimension or unresolved condition.
Below 1.5 m there is no positive-height envelope under this rule, which does not mean a zero-height permit has been approved.
Official sources and rule dates
Sources were checked on 2026-09-09 through the National Law Information OPEN API.
The review used Building Act ID 001823 / MST 273437, Article 61, and Enforcement Decree ID 002118 / MST 288339, Articles 86 and 119.
The current-law status, promulgation and effective dates were checked together.
No case-law damages estimate or invented rate is used in the calculation.
- Building Act, Article 61 (Korean official text): Act No. 21035, promulgated 2025-08-26, effective 2026-02-27
- Enforcement Decree, Article 86 (Korean official text): Presidential Decree No. 36541, promulgated and effective 2026-07-28
- Enforcement Decree, Article 119 (Korean official text): assessment datums, building heights and related exceptions
2026-07-28 is the effective date of the checked consolidated Decree version, not the original introduction date of the 10 m band.
Latest local ordinance and district-plan amendments, as well as transitional provisions for older permits, require individual verification.
When rules change, recheck applicability and boundary treatment as well as the numeric thresholds.
Bring the review to your design consultation
Confirm that every entered height and due-north boundary distance matches the drawings.
For shortfall rows, prepare alternatives with a larger setback or a lower height, and keep unresolved conditions as questions for the architect.
Send the CSV with zoning information, the cadastral map, site plan and building sections so the design assumptions can be checked together.