When and how
| When | How | Notes |
|---|---|---|
| 1–31 May of the next year | Comprehensive income tax return | Add deductions missing from the settlement |
| Within 5 years after that | Correction claim (gyeongjeong cheonggu) | Amend the filed figures on Hometax and request a refund |
Both can be done on Hometax yourself, without going through HR.
Commonly missed items
- Medical expenses not in the simplified data (for example, glasses from a shop that did not report)
- Dependents who met the income rules but were not declared (residents only)
- Card spending at a previous employer (see job changes)
Steps
- Look up last year’s settlement (withholding receipt) on Hometax.
- Collect proof for the missing items.
- In May use the income tax return; after that, the correction claim menu. Change the deduction amounts and Hometax recalculates the refund.
If instead you over-claimed (a dependent claimed twice, for example), amending before the NTS finds it keeps penalties lower.
Estimating the extra refund
Save the original result
Enter figures matching your withholding receipt and save the scenario as “original”.
Add the missing items and compare
Add the missing medical or card amounts, save as “with missed items”, and compare. The app covers medical, card, housing savings and dependents only; education and donations are not modelled.
The app’s English screens show amounts with the Korean won sign, and the saved-scenario card keeps a few Korean labels in the current version.
FAQ
Will my employer know?
No. The correction claim is filed by you on Hometax.
What about years older than five?
Once the deadline passes, a refund is generally no longer possible. Start with the oldest year.
Sources: eToday, missed deductions can be claimed for 5 years (Korean) · NTS Hometax
Year-End Tax Calculator
No sign-up, works offline, and your salary data stays on your phone. Free on Android, in English and Korean.