If the calculator gave you a smaller Korean National Pension than you hoped for, there are still ways to raise it.
1. How much does it add. Every extra insured year adds 5% of the basic pension, for life — 50% at ten years, 100% at twenty, 200% at forty (our calculation). That is why filling gaps beats paying more.
2. What is the catch. Retroactive payment is capped at “under ten years” — at most 119 months including military service. And the contribution is priced on the standard monthly income at the date of application, not the income you had back then, so the higher your income now, the more it costs.
3. In what order. Under ten insured years, get to ten first via continued voluntary membership and retroactive payment; if you once took a lump-sum refund, look at repayment (check the interest rate for the year you took it); for gaps, retroactive payment; with other income, deferral.
How much does one more year add
The benefit formula explains it. The old-age payment rate is 50% at ten insured years, plus 5% for every year beyond ten.
10 years = 50% · 20 years = 100% · 30 years = 150% · 40 years = 200% (our calculation)
Each additional year adds 5% of the basic pension, for life. The structure is in our National Pension guide.
① Retroactive payment — how far back can it go
You can pay contributions for months you missed through unemployment, business closure or a career break, and have them counted as insured months. The source calls it “a scheme that adds insured months equal to the months paid; it is not compulsory.”
| Item | What the source says |
|---|---|
| Ceiling | Under ten years · 119 months maximum, military service included |
| Eligibility | Currently reporting income, or a voluntary / continued-voluntary member |
| How it is priced | [standard monthly income in the month you apply] × [rate in the month payment is due] × months |
| Instalments | Up to 60 monthly instalments (interest added at the one-year deposit rate) |
| Required document | A detailed marriage certificate — the application cannot be processed without it |
The pricing rule is what matters. The bill is based on your income now, not your income then. A higher current income makes back-payment more expensive, so applying during a low-income stretch buys the same months for less.
Voluntary members face a ceiling — the source caps the underlying contribution at the A value × the contribution rate. With the 2026 A value of ₩3,193,511 that is ₩303,384 a month (our calculation: 3,193,511 × 9.5%).
The marriage-certificate requirement is easy to miss. The source states that the application “cannot be processed” without it, and that a pre-2008 divorce or bereavement requires an additional family register extract.
② Repaying a lump-sum refund — always worth it?
If you once took a lump-sum refund on leaving Korea or leaving work, you can repay it with interest and restore those insured months. The appeal is that older periods carry a much higher proportional constant — 2.4 for 1988–1998 against 1.29 today.
But that comparison needs care. In the source's formula the 1988–1998 term uses (A + 0.75B), multiplying your own income B by 0.75, while every later term uses (A + B). The constant looks nearly double; the inputs are not the same.
We also obtained the full table of yearly interest rates.
| Year | Rate | Note |
|---|---|---|
| 1988–1993 | 10% | six years at the maximum |
| 2000 | 7.0% | — |
| 2010 | 2.8% | — |
| 2021 | 0.7% | lowest in the table |
| 2023 | 3.5% | rising again |
| 2026 | 2.2% | current |
The 10% high and the 0.7% low are a factor of 14.3 apart (our calculation). “Repayment costs a lot in interest” is a completely different statement depending on the year you took the refund.
The number of instalments also varies — 3 for under a year of restored coverage, 12 for one to five years, 24 for five years or more.
What we could not verify — the source says only that interest applies “from the month the refund was paid to the month before the application.” Whether it compounds is not stated, so this article does not compute a repayment total.
③ Continued voluntary membership · ④ Voluntary membership
- Continued voluntary — compulsory membership ends at 60, but you may keep paying until 65. The surest route to the ten-year minimum, and beyond it each year still adds 5 percentage points to the payment rate.
- Voluntary — you can join even with no earned income. If both spouses join, both draw a pension later.
⑤ Credits — what changed in 2026
Credits add insured months without contributions. The source prints two tables, and setting them side by side makes the change visible.
| Children | Previous (from the second, capped at 50) | From 2026 (from the first, no cap) | Change |
|---|---|---|---|
| 1 | not counted | 12 months | new |
| 2 | 12 months | 24 months | +12 |
| 3 | 30 months | 42 months | +12 |
| 4 | 48 months | 60 months | +12 |
| 5 | 50 months (cap) | 78 months | +28 |
Two, three and four children all gain a flat 12 months — five gains 28 (our calculation), because the 50-month cap is gone. The more children, the larger the effect of this change.
The new table has its own pattern — only the step from one child to two adds 12 months; after that each additional child adds 18 (12 → 24 → 42 → 60 → 78, our calculation).
The credited income differs by credit type. From the source —
· Childbirth credit: those months count at the A value → ₩3,193,511 in 2026
· Military credit: those months count at half the A value → ₩1,596,756 (our calculation)
The same “one month” is worth twice as much under the childbirth credit.
- Military credit (Article 18) — 6 months if service ended before 1 January 2026; from then on, the actual service period of six months or more, up to 12 months. Applies to those enlisting from 1 January 2008.
- Parents must agree. The childbirth credit goes to one parent only. An agreement must be filed within one month of the first claim; miss the deadline and the months are split equally.
- Unemployment credit (Article 19-2, since August 2016) — pay 25% yourself and the state covers 75%, for up to 12 months. Credited income is 50% of pre-unemployment average pay, capped at ₩700,000. At the cap your share is ₩16,625 a month (700,000 × 9.5% × 25%, our calculation). Eligibility for the underlying benefit is in our unemployment benefit calculator.
You do not apply for credits. The source: “the Service verifies and adds them when you claim your pension.”
⑥ Deferral — moving the start date
Deferring the start by up to five years adds 7.2% for each deferred year (0.6% a month) under Article 62. You may defer part rather than all — 50, 60, 70, 80 or 90%. The trade-off is worked through in early versus deferred.
What does it cost to pay
Paying back-contributions or a refund repayment by card carries a fee. The source: “note the collection fee of 0.8% for credit cards (0.5% for debit cards); the fee is borne by the payer.”
- 0.8% credit, 0.5% debit — a ₩10 million back-payment costs ₩80,000 more on a credit card (our calculation).
- Foreign and corporate cards cannot be used.
- Direct debit is taken on the 25th, with a notice the day before and an error message two days after.
What order to work through
- Under ten insured years → continued voluntary membership and back-payment, to reach ten first. Below ten there is no pension at all.
- You once took a refund → consider repaying. Check the rate for that year in the table above before anything else.
- You have gaps → back-payment, remembering the 119-month ceiling and the current-income pricing.
- Childbirth, military service or unemployment in your history — the first child now counts, from 2026.
- Other income in retirement → defer.
Questions that remain
How much can I back-pay?
119 months at most including military service — 9 years and 11 months. The “under ten years” ceiling is explicit in the source.
Is it priced on my income at the time?
No — on the standard monthly income in the month you apply. A high current income makes it more expensive.
Is repaying a refund always worth it?
Usually, but the interest rate depends on the year. A refund taken between 1988 and 1993 carries 10%. That same period also has the highest constant (2.4), so the two have to be weighed together.
Do I have to apply for credits?
No — the Service adds them automatically when you claim. But the childbirth credit needs a parental agreement, and missing the deadline splits it.
What if I lose membership?
You cannot apply once membership lapses. Applications already filed may still be paid unless the collection right has expired.
Sources
- National Pension Service — agency source — “Retroactive payment of contributions” (checked 30 July 2026). Source for the under-ten-years / 119-month ceiling, the pricing formula, the voluntary-member cap, the 60 instalments, the marriage-certificate requirement and the eligible periods.
- National Pension Service — agency source — “Repayment of a lump-sum refund” (same date). Source for the full 1988–2026 interest rate table, the 3 / 12 / 24 instalment counts and the repayment basis.
- National Pension Service — agency source — “Pension benefits — credit schemes” and “benefit calculation.” Source for the two childbirth credit tables, the military credit at half the A value, the unemployment credit (25% / 75%, ₩700,000 cap), the parental agreement rule, the payment rate, the A value and the constants 2.4 and 1.29.
- National Pension Service — agency source — “How to pay repayments and back-contributions.” Source for the 0.8% credit and 0.5% debit card fees, the exclusion of foreign and corporate cards, and the 25th-of-the-month direct debit.
- Our own calculation — 119 months as 9 years 11 months, the ₩303,384 voluntary cap, the 14.3x interest spread, the childbirth credit differences (+12, +28) and the +18 pattern, the ₩1,596,756 military credited income, the ₩16,625 unemployment share, the payment rates by insured years and the ₩80,000 card fee on ₩10 million are ours.
Where to check further
- Whether repayment interest is simple or compound. The source states only the period, not the method, so this article does not compute a repayment total — the National Pension Service (1355) produces the actual figure from your refund record.
- How long it takes to recover a retroactive payment or repayment. It depends on your own record, so the source cannot state it — the same call gives you “pay this much, gain this much.”
- How the “first child from 2026” and “second child from 2008” childbirth tables interact. The page prints two tables with no merge rule — a local Service branch can settle it against your children's birth years.
As of July 2026. The ceilings, formulas, rate table and credit tables are the National Pension Service's own; the differences, ratios and conversions are our arithmetic. Whether any of this pays off depends on your record — check with the Service (1355). The scheme overall is in our National Pension guide, estimates in the calculator, timing in early versus deferred, and the wider picture in retirement preparation by age.
