Korea’s National Pension old-age pension needs at least 10 years of membership (National Pension Act Art. 61(1)). But you cannot simply count from your first day at work to your last. Article 17(1) counts membership in months, from the month after the month you joined to the month containing the day before you lost membership — except that joining on the 1st counts that month. Leaving a job ends membership the next day (Art. 12), so joining on 15 March and leaving on 31 October gives April to October, 7 months. Enter your dates and any unpaid months to see the months counted.
1. From the month after you join to the month of the day before you lose membership, counted in months (Art. 17(1)).
2. The joining month counts if you joined on the 1st, joined as a continued voluntary member, or ask for it (items 1–3).
3. Unpaid periods are left out — if your employer deducted your share but did not pay, half that period counts (Art. 17(2)).
Calculator
Updates as you type. Months the employer failed to pay after deducting your share count by half, with part months rounded up to one (Art. 17(2)). Months after the arrears notice (Art. 17(3)) and the service, childbirth and unemployment credits are not modelled.
How membership is counted — Art. 17
| Type | What the source says | Worth noting (ours) |
|---|---|---|
| Rule (1) | In months, from the month after the month you joined to the month containing the day before you lost membership | The joining month usually drops out |
| Item 1 | Joined on the 1st of the month: that month counts — unless you lose membership in the same month | Join 1 March, leave 20 March: 0 months |
| Items 2–3 | Also counted when joining as a continued voluntary member, or at your request | Asking means paying for that month too, as we read it |
| No double count (1) proviso | Rejoining in the month of the day before you lost membership: that month is not counted twice | Changing jobs within a month |
| Unpaid (2) | Periods without contributions are not counted. If the employer deducted your share and did not pay, half counts, part months as one | 5 months unpaid gives 3 (our sum) |
| After an arrears notice (3)–(4) | Once the health insurance service notifies you, unpaid months from the next month are not counted. Pay your share and half counts; pay both shares and all counts. After 10 years from the due date, interest is added | Employer arrears have their own article |
| Refunds (6) | A refund lump sum that must be returned but is not: that period is not counted | — |
When membership starts and ends — Arts. 11–12
| Type | What the source says | Worth noting (ours) |
|---|---|---|
| Workplace member joins (Art. 11(1)) | When hired or becoming the employer, or when the workplace becomes covered | Your start date |
| Workplace member loses (Art. 12(1)) | Death, loss of nationality or emigration, end of employment, turning 60: the next day. Becoming excluded: that day | The day after your last day |
| Regional member loses (Art. 12(2)) | Mostly the next day; on becoming a workplace member or excluded, that day | A new job ends regional membership that day |
| Voluntary member joins (Art. 11(3)) | The day the application is accepted | — |
The calculator’s “membership lost” field picks a row from this table: leaving a job, death or turning 60 is “the next day”; cases that end the same day are “the same day”.
Four sums — our examples
| Case (our example) | Membership | Worth noting (ours) |
|---|---|---|
| Join 15 Mar 2026, leave 31 Oct | Lost 1 Nov → April–October, 7 months | 8 if you ask for March |
| Join 1 Mar 2026, leave 31 Oct | 1st-of-month join counts March: 8 months | Art. 17(1) item 1 |
| Join 1 Mar 2026, leave 20 Mar | Lost in the joining month → 0 months | 1 if you ask |
| Join 1 Jan 2026, leave 31 Dec; employer withheld but did not pay 5 months | 12 − 5 + 3 = 10 months | Half of 5 is 2.5; part months count as one, so 3 |
A job change works the same way. Work at firm A from 1 January to 15 March (lost 16 March; January to March, 3 months) and join firm B on 20 March, and firm B counts from April. Because you rejoined in March, March is not counted twice even if you ask (Art. 17(1) proviso).
Ways to make up a shortfall are in National Pension make-up contributions and continued voluntary membership after 60. Credits are in military service credit, childbirth credit and unemployment credit; employer arrears in when your employer doesn’t pay.
Checklist
- ☐ Did you join on the 1st?
- ☐ Membership ends the day after your last day
- ☐ Any months without contributions?
- ☐ If your employer withheld but did not pay, any arrears notice?
- ☐ Does everything add up to 120 months (10 years)?
Questions that remain
I paid in my first month — why does it drop out?
Art. 17(1) counts from the month after you join. Unless you joined on the 1st, the month counts only if you ask (item 3). Check what was actually deducted in the agency’s records.
What happens at 60?
Workplace members lose membership the day after turning 60 (Art. 12(1) item 4). Paying on after that is continued voluntary membership.
Sources
- Korean law database (law.go.kr) — National Pension Act Arts. 11, 12, 17, 61 — source (current text, effective 20 October 2026, Act No. 22096; checked 2 November 2026). When membership starts and ends (workplace, regional, voluntary), monthly counting and items 1–3, no double count on rejoining, unpaid periods and the half rule (part months as one), arrears notices and 10-year interest, unreturned refunds, the 10-year old-age requirement.
- Not read. Decree details for partly paid months (Art. 17-2), the details of the credits (Arts. 18, 19, 19-2), the Decree and Rule.
- What we added. The “worth noting” column and the Korean everyday gloss.
Where to check further
- National Pension Service — your monthly contribution record shows the months actually counted.
Written on 2 November 2026. The content is from the source; the glosses are ours.
