Missed rent, medical or dependant deductions at year-end settlement can be recovered with a refund claim (gyeongjeong cheonggu). Article 45-2 of the Framework Act on National Taxes allows it “within five years after the statutory filing deadline”. But an employee who only had year-end settlement never filed a return. Paragraph 5 of the same article therefore reads the phrase, for withholding cases, as “after the payment deadline of the year-end settled or withheld tax”. That deadline is usually 10 March of the next year, so as of October 2026 tax year 2021 settlements can be claimed until 10 March 2027 (our sum). Enter the tax year and type to get the last day.
1. Refund claim window = five years after the statutory deadline (Art. 45-2(1)).
2. Year-end settlement only: five years after the settled tax’s payment deadline (usually 10 March of the next year) (Art. 45-2(5)).
3. Later events: 3 months from learning of them; the tax office replies within 2 months (Art. 45-2(2), (3)).
Calculator
Updates as you type. The five years run from the day after the deadline under the Civil Act method (Art. 4); a deadline on a Saturday or Sunday moves to the next day (Art. 5). Public holidays, substitute holidays and Labour Day also move a deadline under Art. 5, but this calculator moves only weekends — check those yourself.
The claim periods — the text
| Type | What the source says | Worth noting (ours) |
|---|---|---|
| Art. 45-2(1) | A person who filed by the statutory deadline may claim a decision or correction where the tax exceeds what was due or a refund was short, within five years after the statutory filing deadline. Tax increased by a decision may be contested within 3 months of learning of it (still within the five years) | Missed deductions fall under subparas. 1 and 2 |
| Art. 45-2(2) | Where a later event occurs (a ruling, a mutual agreement, reattribution and so on), a claim may be made within 3 months of learning of it, notwithstanding para. 1 | The route that stays open after five years |
| Art. 45-2(3) | The tax office must decide, or notify that there is no reason to, within 2 months of receiving the claim; without a notice, objections and appeals may start the day after the 2 months | — |
| Art. 45-2(5) | Paras. 1–4 apply to withholding cases (wage income and others); “after the statutory filing deadline” reads as “after the payment deadline of the year-end settled or withheld tax”. The withholding agent or the person withheld may claim | An employee may claim directly |
| Arts. 4 and 5 | Periods are counted under the Civil Act unless provided otherwise. A filing, claim or payment deadline falling on a Saturday, Sunday, public or substitute holiday, or Labour Day moves to the next day | Labour Day was added by the 11 Nov 2025 revision |
The full claim process and the deductions most often missed are in refund claims — missed deductions within five years, and why some deductions never appear in the simplified data is in deductions missing from the simplified service. This page only counts the exact day the five years end.
Which deadline the five years run from
| Type | Base deadline | Basis and notes (ours) |
|---|---|---|
| Year-end settlement only | 10 March of the next year | Income Tax Act Art. 137: settlement when paying February wages of the next year. Art. 128(1): withheld tax is paid by the 10th of the month after withholding, so 10 March for February (our sum) |
| Workplace on half-yearly payment | 10 July of the next year | Art. 128(2): approved agents pay by the 10th of the month after the half-year, so February falls in January–June and the date is 10 July (our sum). Ask your employer |
| Final income tax return | 31 May of the next year | Art. 70(1): file from 1 May to 31 May |
| Sincere-filing confirmation | 30 June of the next year | Art. 70-2(2): from 1 May to 30 June with the confirmation |
If you also filed an income tax return in May for other income, that return’s deadline (31 May) is the base. If unsure, count from the earlier 10 March and you won’t miss it (our note).
Last days by tax year — our sums
| Tax year · type (our example) | Last day to claim | Worth noting (ours) |
|---|---|---|
| Tax year 2020 · settlement | 10 March 2026 | Already passed |
| Tax year 2021 · settlement | 10 March 2027 | Oldest year open as of October 2026 |
| Tax year 2021 · final return | 31 May 2027 | A Monday, no move |
| Tax year 2023 · settlement | 12 March 2029 | 10 March 2024 was a Sunday, so 11 March; five years on, 11 March is a Sunday again |
| Tax year 2024 · final return | 3 June 2030 | 31 May 2025 was a Saturday, so 2 June; five years on, 2 June is a Sunday |
Where a weekend moved the base deadline, we read the five years as running from the moved day, because Art. 5 makes “the next day the deadline”. If the last day is a public holiday, move it once more yourself. If you plan to claim near the end, check with the tax office.
After five years — the 3-month later-event route
Art. 45-2(2) lets you claim within 3 months of learning that one of these happened later, even for a year past five years:
- The transaction behind the tax was fixed differently by an appeal decision or a court ruling
- A decision moved the income to a third party
- A treaty mutual agreement differed from the original return
- A decision made a linked tax or linked period overpaid
- Decree Art. 25-2: a permit was cancelled; a contract was rescinded or cancelled for an unavoidable reason; books were seized and the obstacle has gone; or a similar event
After you claim — 2 months
The tax office must reply within 2 months of receiving the claim (para. 3). If it can’t decide in time it must tell you the progress and that you may appeal (para. 4); with no notice, appeals may start the day after the 2 months. A refund arising from a claim carries refund interest (Art. 52(3)1) — worked out in the tax refund interest calculator.
Checklist
- ☐ Settlement only, or a May return as well?
- ☐ Is the workplace on half-yearly payment (10 July)?
- ☐ Last day on a public holiday: one more day
- ☐ After five years, a later event still gives 3 months
- ☐ No reply in 2 months: appeal route opens
Questions that remain
Does my employer have to claim for me?
Para. 5 says the withholding agent or the person withheld may claim. You can do it yourself.
Does the calculator move public holidays?
No. Art. 5 moves public and substitute holidays and Labour Day too, but the calculator moves only Saturdays and Sundays.
Is it five years for tax the office increased?
For tax increased by a decision, it is 3 months from learning of it (from receipt if notified), and still within five years of the deadline (para. 1 proviso).
Sources
- Korean law database (law.go.kr) — Framework Act on National Taxes Arts. 4, 5, 45-2 and 52 — source (current text, effective 2 October 2026, Act No. 21987; checked 27 October 2026). Civil Act counting, the deadline extension rule (weekends, public and substitute holidays, Labour Day), the five-year window and 3-month rule for increases, later events, the 2-month reply and appeals, withholding cases (settled tax payment deadline), refund interest on claims.
- Korean law database — Enforcement Decree Art. 25-2 — source (effective 1 July 2026, Decree No. 36125; checked 27 October 2026). The four later-event grounds.
- Korean law database — Income Tax Act Arts. 70, 70-2, 128 and 137 — source (effective 1 July 2026, Act No. 21221; checked 27 October 2026). 31 May final return, 30 June sincere filing, withheld tax by the 10th of the next month or half-yearly, February settlement.
- Not read. The Civil Act period articles (not re-read; method as in the legal period calculator), NTS rulings and case law, local income tax claims.
- What we added. The “worth noting” column and the Korean everyday gloss.
Where to check further
- Your tax office — when the last day meets a holiday, and whether your employer pays half-yearly.
Written on 27 October 2026. The content is from the source; the glosses are ours.
