Korea gives foreign employees a choice most locals don’t have: pay income tax at the normal progressive rates (6–45% plus local tax), or elect a flat 19% on gross employment income (20.9% including local tax) and walk away from the entire deduction system.
What trade are you making?
The flat rate looks clean, but electing it means giving up the earned-income deduction, personal deductions, insurance-premium deductions, and the earned-income tax credit — the machinery that makes Korea’s progressive system far gentler than its headline brackets suggest. For a typical salary around 50,000,000 KRW, the progressive route’s effective income-tax rate lands in the single digits. Paying a flat 20.9% on that same salary would cost millions of won more per year.
So who actually benefits?
High earners. With standard deductions only, the crossover sits very roughly in the 150–200 million KRW range — below that, progressive almost always wins; above it, the flat rate starts saving real money. Executives, specialist engineers on expat packages and finance professionals are the typical users. The election is generally available for up to 20 years from your first working day in Korea.
How to elect it
Tell your company’s payroll team — they file the flat-rate application with your withholding, or you can apply it at year-end tax settlement (yeonmal-jeongsan). You can switch methods between years, so a raise that pushes you past the crossover is a reason to re-run the numbers, not a missed boat.
One adjacent perk worth knowing: when you leave Korea permanently, nationals of many countries can claim their National Pension contributions back as a lump sum. That refund often outweighs a year of tax optimization, and almost nobody plans for it.
Frequently asked questions
Who can use the 19% flat tax in Korea?
Foreign employees working in Korea can elect the flat rate on Korean employment income, generally for up to 20 years from their first day of work in Korea. It applies to employment income only, not business or rental income.
Does the flat tax include local income tax?
No. The 19% is national income tax; local income tax adds 10% of that amount, so the effective combined rate is 20.9% of gross employment income.
Do I still pay social insurance under the flat tax?
Yes. National Pension, health insurance, long-term care and employment insurance are deducted regardless of which income tax method you elect.
This guide is general information, not tax advice. Confirm your situation with a tax professional or the NTS.