What this Korea construction-delay calculator estimates
Construction-delay liquidated damages are a contractually agreed estimate of loss when a contractor does not complete the works by the agreed deadline. This calculator multiplies a selected calculation base by the daily liquidated-damages rate and attributable delay days, then applies non-attributable periods, an agreed or statutory cap, and any amount already withheld, paid, or set off. It shows three bases side by side so the employer and contractor can identify where their interpretations diverge.
The word “delay damages” on this page refers to delayed completion of construction works. It is not statutory interest on an overdue monetary debt, so this tool does not apply the Korean civil, commercial, or litigation interest rates of 5%, 6%, or 12% per year. Use the separate late-interest or unpaid-construction-payment tools for those questions.
Korea-based legal planning only
This English page explains Korean rules verified on August 23, 2026. The result is not a legal entitlement, a valid withholding instruction, or a prediction of a Korean court award. Attribution, completion, partial acceptance, termination, excessive-liquidated-damages reduction, tax treatment, and the governing contract require case-specific Korean legal review.
Useful decision moments
- An owner or employer is considering a deduction for late completion
- A contractor is separating approved extensions and employer-caused delay
- A Korean public authority has inspected and accepted a divisible completed part
- The parties disagree on total-contract versus remaining-contract calculation bases
- Counsel needs a transparent date-and-document schedule before negotiation or litigation
Korean legal framework verified for 2026
Article 398 of the Korean Civil Act allows parties to agree damages in advance for non-performance. If the agreed amount is unduly excessive, a court may reduce it to an appropriate amount; this calculator does not predict or apply that reduction. Article 664 defines a contract for work around completion of the promised work and payment for its result, making the completion date and contractual definition of completion central issues.
Comparison of Korean private, central-government, and local-government works delay rules| Contract scope | Daily rate | Cap | Primary source |
|---|
| Private works | Enter the signed contract rate | Enter the contractual cap | Contract wording and Civil Act Article 398 |
| Central-government works | 0.05% per day | 30% of the applicable base | State Contracts Decree Article 74 and Rule Article 75 |
| Local-government works | 0.05% per day | 30% of the applicable base | Local Contracts Decree Article 90 and Rule Article 75 |
What the Korean public-works rules add
Article 74 of the State Contracts Decree and Article 90 of the Local Contracts Decree exclude days for which the contractor is not responsible. If an inspected, accepted, and divisible completed part has been taken over, its corresponding amount is deducted from the contract amount before calculating delay damages. Both regimes cap the result at 30% of that applicable base, and their current rules set the works rate at 0.5 per thousand, or 0.05%, for each day.
Do not copy the public preset into a private contract
The 0.05% rate and 30% cap are not universal Korean market standards and are not automatic defaults for every private building contract. A private project must use the executed contract and incorporated general conditions. Goods, services, transport, and other public contracts also use different statutory rates, so this works-only preset must not be reused for them.
Formula and calendar logic
Attributable delay days
Raw delay starts on the day after the agreed completion date and ends on the entered actual-completion or reviewed-end date. Each exclusion is clipped to that delay window. Overlapping exclusions are merged into a date union so the same date is never deducted twice.
Amount by scenario
The calculator rounds each provisional amount to the nearest Korean won. If a cap is enabled, it uses the lower of the gross amount and the base multiplied by the cap percentage. Prior settlement is then deducted without allowing the net provisional amount to fall below zero.
Attributable days = max(raw delay days − union of valid exclusion days, 0)
Gross amount = base amount × daily rate ÷ 100 × attributable days
Capped amount = min(gross amount, base amount × cap rate ÷ 100)
Net provisional amount = max(capped amount − prior settlement, 0)
Understanding the three calculation bases
1. Total contract amount
This models an interpretation that applies the daily rate to the entire contract amount. Confirm final variations, price adjustments, annual portions of a long-term contract, VAT treatment, and any contractual redefinition of the contract amount before relying on it.
2. Amount remaining after inspected and accepted work
The calculator subtracts the entered accepted-work amount from the total contract amount. The Korean public-works provisions require more than a percentage-of-progress estimate: the completed part must have been inspected, accepted, and divisible. The calculator displays this scenario but does not decide whether those conditions are satisfied.
3. Custom contractual base
Use this for a separately stated base, an annual contract portion, or another interpretation supported by the contract. It is deliberately a manual amount because the calculator cannot infer how a variation, termination, joint venture allocation, or special condition changes the base.
Step-by-step workflow
- Choose the contract scope. Select private terms, Korean central-government works, or Korean local-government works.
- Enter all three bases. Keep the total amount, accepted completed-work amount, and custom base separate rather than silently choosing one.
- Set the calendar boundary. Use the agreed completion date and an actual-completion or legally reviewed scenario end date supported by records.
- Add exclusion periods. Record approved extensions, employer instructions, force-majeure review periods, and other asserted non-attributable periods with inclusive dates.
- Verify rate, cap, and prior settlement. The signed contract and current rule prevail over any on-screen preset.
- Export the reasoning, not just the amount. Keep the date schedule, scenario base, warnings, and missing evidence with the provisional result.
Worked example: overlapping exclusions on Korean public works
Assume a KRW 500,000,000 central-government works contract, KRW 100,000,000 of inspected and accepted completed work, and a KRW 350,000,000 custom contractual base. The agreed completion date is June 30, 2026, and the entered completion date is August 10, producing 41 raw delay days. Exclusions cover July 1–5, July 4–7, and July 20–21. Those ranges contain 11 days when counted separately but overlap by two days, so the union is nine days and attributable delay is 32 days.
Worked example comparing three Korean public-works liquidated-damages bases| Scenario | Base | 0.05% × 32 days | After KRW 1,000,000 settled |
|---|
| Total contract | KRW 500,000,000 | KRW 8,000,000 | KRW 7,000,000 |
| After accepted work | KRW 400,000,000 | KRW 6,400,000 | KRW 5,400,000 |
| Custom base | KRW 350,000,000 | KRW 5,600,000 | KRW 4,600,000 |
None of these figures reaches the 30% cap. By contrast, applying 0.05% for 800 attributable days to a KRW 100,000,000 base produces KRW 40,000,000 before the cap and KRW 30,000,000 after it. The example is a deterministic formula check, not a market norm or recommended contract position.
How to interpret the result
A large scenario spread is a base-amount dispute
If the three net amounts differ materially, resolve the contractual base and partial-acceptance conditions before spending time debating individual delay days. The spread is an issue-spotting measure, not a probability range.
Prevented overlap reveals evidence collisions
A date can be supported by both an extension approval and an employer instruction but can be deducted only once. A high overlap count is a cue to map each notice to the affected critical-path activity and approved period.
Prior settlement can expose a repayment or double-counting issue
The calculator never reports a negative net amount. If prior withholding, payment, or set-off exceeds a scenario, review whether it belongs to a different claim, was already credited elsewhere, or may be disputed as an overpayment. The tool does not determine repayment liability.
Stopped or terminated works need a separate end-date analysis
In Supreme Court case 2009Da41137 and 2009Da41144, decided January 28, 2010, the delay period in a stopped-and-terminated project was not mechanically cut off on the actual termination date. The Court described a period running from the day after agreed completion to the point at which the employer could have terminated and then completed the works through another contractor, excluding time for which the original contractor was not responsible. The calculator therefore asks for a reviewed scenario end date and does not invent procurement, remobilisation, or replacement-contractor duration.
In Supreme Court case 2009Da7212 and 2009Da7229, decided January 14, 2010, the Court distinguished incomplete works from completed works that still had defects. Completion is assessed objectively against the contract and good faith, rather than solely by whether the employer conducted a completion inspection. A special agreement that genuinely makes inspection acceptance the liquidated-damages end point may change the analysis, so the calculator does not automatically choose between physical completion, use approval, and inspection acceptance.
Evidence checklist for negotiation or review
- Contract terms: contract amount, completion date, daily rate, base, cap, and extension procedure
- Completion records: programme, completion submission, use or handover evidence, inspection requests, and defects list
- Extension records: variations, suspensions, employer instructions, force-majeure notices, approvals, and replies
- Partial acceptance: progress inspection, actual possession or use, acceptance, and evidence that the part is divisible
- Settlement records: payment certificates, withholding notice, payment or set-off agreement, invoices, and final account
Recommended chronology columns
Record the date, event, asserted responsibility, affected activity, evidence file name, notice date, response, and approval status in one row. Where two grounds cover the same day, keep the primary and supporting evidence together while deducting that day once.
Frequently asked questions
Do all Korean private works contracts use 0.05% per day and a 30% cap?
No. Those are the verified 2026 central- and local-government works settings. A private project uses its signed contract and incorporated conditions, subject to the Civil Act and case-specific review.
Is the agreed completion date itself counted as a delay day?
This calculator starts on the following day. Completion one day after the agreed date produces one raw delay day, unless the contract validly defines a different counting rule.
Are all employer-caused dates automatically excluded?
No. The instruction or event, its effect on completion, notice requirements, extension application, approval, mitigation, and critical-path connection all require evidence.
Can a progress percentage be used as the accepted-work deduction?
Not automatically. The Korean public-works provisions refer to an inspected and accepted, divisible completed part. This calculator asks for a confirmed amount rather than deriving it from a percentage.
Can the calculator estimate a Korean court reduction under Civil Act Article 398?
No. Whether the amount is unduly excessive and how much to reduce it depend on the contract purpose, bargaining position, actual loss, delay circumstances, and other case-specific factors.
Does a defects-repair period always remain in the delay period?
Not necessarily. Korean case law distinguishes incomplete works from completed but defective works, while a genuine special inspection-acceptance clause may affect the end point.
Can an employer claim separate losses above liquidated damages?
That depends on what breach the liquidated-damages clause covers and how other damages clauses are drafted. Case 2009Da41137 and 2009Da41144 explains that separate defective-performance losses are not always absorbed into completion-delay liquidated damages, but an actual claim needs legal review.
Official sources and update date
- Korean Civil Act, law ID 001706, MST 284415, Articles 398, 664, and 665, effective March 17, 2026
- State Contracts Decree, law ID 002652, MST 285893, Article 74, effective June 3, 2026
- State Contracts Rule, law ID 006590, MST 282607, Article 75, effective January 2, 2026
- Local Contracts Decree, law ID 010098, MST 286149, Article 90, effective June 3, 2026
- Local Contracts Rule, law ID 010153, MST 287365, Article 75, effective July 1, 2026
- Supreme Court 2009Da7212 and 2009Da7229, precedent serial 143641, decided January 14, 2010
- Supreme Court 2009Da41137 and 2009Da41144, precedent serial 237145, decided January 28, 2010
The current-history status, effective dates, articles, and precedent records were checked through the Korean National Law Information OPEN API on August 23, 2026. Recheck the rules, cases, standard conditions, and executed contract whenever the law or project documents change.
Return to the calculator with the contract and chronology
Enter the actual daily rate and completion dates first, then add each asserted exclusion as a documented date range. Keep the three-base comparison, overlap warning, and missing-evidence list together for negotiation or qualified Korean legal review.