November interim income tax — who gets a bill and who does not
In early November, a freelancer who paid comprehensive income tax the previous May receives a tax office bill: ₩2M. Work halved this year, yet the freelancer next door received none, having paid ₩900,000 last year. Interim payment is a system for paying half of last year's tax in advance by 30 November; it is not collected when that half is under ₩500,000; and if the first half-year's tax comes to less than 30% of last year's base, you may file an estimate on actual results instead. What is paid in November is deducted at the following May's final return.
Conditions used in the calculation
- Case
- last year's final tax ₩4M · ₩900,000 · ₩1M · ₩30M · first-half income ₩10M · ₩20M · ₩50M
- Step ①
- base = last year's final tax + last year's interim − refunds · half by 30 November · bills 1 to 15 November · under ₩1,000 dropped · employees and first-year businesses excluded
- Step ②
- exemption: not collected if the amount to be billed is under ₩500,000
- Step ③
- estimate filing: first-half income × 2 − carried losses − deductions → base rates → ÷ 2 − prepaid · file by 30 November if under 30% of the base
- Step ④
- settlement: deducted as prepaid tax at the May final return · split of the excess over ₩10M two months later · above ₩20M up to half · unpaid split rebilled in January
- Caution
- leave the prepaid-tax box on the May return blank and you pay twice
Results
- ₩4M last year
- ₩2M bill (this year's results are not considered at this stage)
- ₩900,000 vs ₩1M last year
- ₩450,000 → no bill · ₩500,000 → bill (a ₩100,000 difference)
- First half ₩10M · deductions ₩3M
- base ₩17M · computed ₩1.29M · half ₩645,000 < the 30% line of ₩1.2M → may file · ₩645,000 instead of ₩2M · ₩1,355,000 kept
- First half ₩20M
- estimate ₩2,145,000 > ₩1.2M → cannot file · pay the bill
- Settlement
- ₩3M for the year · ₩2M in November → ₩1M in May · ₩1.5M for the year → ₩500,000 refund
- ₩30M last year · first half ₩50M · deductions ₩10M
- bill ₩15M · estimate ₩8.03M · ₩6.97M kept
At a glance
With first-half income of ₩10M, filing an estimate of ₩645,000 keeps ₩1,355,000; at ₩20M the 30% line is crossed and the ₩2M bill stands.
- Bill (half of last year's ₩4M)₩2M
- Estimate filing (first half ₩10M)₩645,000
- 30% line (base ₩4M × 30%)₩1.2M
Why it works this way
In early November, a freelancer who paid comprehensive income tax the previous May receives a tax office bill: ₩2M. Work halved this year, so why pay this again? The freelancer next door got no bill the same November, having paid ₩900,000 in tax last year. This is interim payment: half of last year's tax paid in advance this year. It is not collected when under ₩500,000, and if the first half-year's results fall below 30% of last year's, you can file on actual results. Most people simply pay without knowing why the bill comes, whether there is a way not to pay, or what happens the following May. It is often mistaken for a second tax, but it is the same tax paid in two parts: not a new tax but next May's tax paid early on last year's basis, decided within November.
Income Tax Act Article 65(1) and (7) · Article 85.
- Period and deadlineJanuary to June is the interim period · half of last year's tax by 30 November · bills from 1 to 15 November
- Baselast year's final tax + last year's interim − refunds · ₩4M last year → ₩2M bill · under ₩1,000 dropped
- This year's resultsnot considered at this stage · employees excluded · no bill for a first-year business
Being billed on last year's figures even when this year went badly confuses people. Not knowing, you ignore it and pay penalties or pay in full and tie the money up until May.
Step ② Exemption is the ₩500,000 line. If the amount to be billed is under ₩500,000 it is not collected. ₩900,000 last year gives ₩450,000 and no bill; ₩1M gives ₩500,000 and a bill. ₩100,000 of last year's tax decides whether a bill arrives. It is not waived but simply not collected in advance, which confuses people; not knowing, you assume there is no tax and meet May unprepared.
Income Tax Act Article 65(3).
- Orderfirst-half income × 2 − carried losses − deductions → base rates → ÷ 2 − prepaid
- First half ₩10M · deductions ₩3Mbase ₩17M · computed ₩1.29M · half ₩645,000 · 30% of the base = under ₩1.2M → may file · ₩645,000 instead of the ₩2M bill, so ₩1,355,000 is kept
- First half ₩20Mestimate ₩2,145,000 > ₩1.2M → cannot file · pay the bill
Above 30%, the bill stands even if the estimate is small, which confuses people. Not knowing, you pay ₩2M in a halved year and lend ₩1.35M until May.
Step ④ Settlement comes back in May. At the May final return, what was already paid is deducted. ₩3M for the year with ₩2M paid in November means ₩1M in May. ₩1.5M for the year means a ₩500,000 refund, the same tax paid in two parts. A split defers the excess over ₩10M by two months and up to half above ₩20M. With ₩30M last year the bill is ₩15M, but first-half income of ₩50M with ₩10M of deductions gives an estimate of ₩8.03M, keeping ₩6.97M. Miss 30 November and the split portion is rebilled in January with penalties on the rest. Not knowing, you pay twice in May or borrow for lack of a split. The November checklist is three lines: ① last May's final tax, no bill if half is under ₩500,000; ② this year's January to June income × 2, and if the tax ÷ 2 is under 30% of the base, file an estimate by 30 November; ③ apply for a split above ₩10M. With three lines, interim preparation is done, and enter the November amount in the prepaid-tax box of the May return or you pay twice.
All four steps are passed: half of last year, exemption under ₩500,000, estimate filing under 30%, back in May. The reason one got a bill and the other did not was ₩100,000 of last year's tax. Not knowing estimate filing costs ₩1.35M more, a blank prepaid box costs a double payment, missing the 30th brings penalties. Two things to do now: write down half and the 30% line from last May's tax, and on 1 November check the first-half income for estimate eligibility with the 30th on the calendar. Estimates depend on books and expense rates, so consult a tax adviser. Not a new tax, but the first half of the same one.
The legal basis
Drawn from government announcements and the statutes themselves as primary sources, covering only the relevant part.
Income Tax Act Article 65(1) and (7) · Article 85 (Interim payment · Base · Billing)
In force Current (checked 2026-09-05)
A resident with comprehensive income pays half of the interim base (last year's final tax + interim tax − refunds) by 30 November for the interim period of 1 January to 30 June. New businesses and those with only wage income are excluded. Bills are issued from 1 to 15 November.
What this means
Half of last year's tax is paid early in November. This year's results are not considered at this stage.
Income Tax Act Article 86 (Non-collection of small amounts)
In force Current (checked 2026-09-05)
Interim tax under ₩500,000 is not collected.
What this means
Under ₩1M last year means no bill. Not waived, just not collected in advance.
Income Tax Act Article 65(3) (Filing of an interim estimate)
In force Current (checked 2026-09-05)
Where the tax on comprehensive income for the interim period (the estimate) is less than 30% of the interim base, the estimate may be filed and paid by 30 November.
What this means
The exit for a halved year. Above 30% the bill stands even if the estimate is small.
Income Tax Act Article 77 · Enforcement Decree Article 140 · Article 65(2) (Split payment · Rebilling)
In force Current (checked 2026-09-05)
Tax above ₩10M may be split within two months (the excess over ₩10M up to ₩20M, up to 50% above ₩20M). Unpaid interim tax is rebilled the following January.
What this means
₩10M is the door to a split. Past 30 November come penalties and a January rebill.
Run it on your own numbers
The calculator opens with these conditions already filled in. Change the figures and your own case comes straight out.
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Frequently asked
My income fell this year. Why bill me on last year?
The interim bill asks for half of last year's final tax as the base and does not look at this year. If the first half's tax comes to less than 30% of the base, you can file an estimate and pay on actual results.
No bill came. Does that mean no tax?
It only means the amount was under ₩500,000 and not collected in advance. At ₩900,000 last year, half is ₩450,000 so there is no bill, but the May final return is unchanged.
When can I file an estimate?
When half the tax on first-half income × 2 less carried losses and deductions at base rates is under 30% of the base. First-half income of ₩10M with ₩3M of deductions gives ₩645,000, under ₩1.2M, so yes; at ₩20M it is ₩2,145,000, so no.
What happens to the money paid in November?
It is deducted as prepaid tax at the May final return. On ₩3M for the year you pay only ₩1M in May; on ₩1.5M you get ₩500,000 back. Leave the prepaid box blank and you pay twice.
What if I cannot pay it at once?
Above ₩10M the excess can be split two months later, and above ₩20M up to half. Miss 30 November and the split portion is rebilled in January with penalties on the rest.
Do employees make interim payments?
No. Those with only wage income and those who started a business this year are excluded.
Results are estimates based on the inputs and on the rules as at the stated date. They may differ from a lender's actual assessment, and the rules change often. Take professional advice before any decision that matters.