Income Tax in Korea

Most foreign employees in Korea do very little about tax, because it is withheld from payroll and reconciled once a year. The two decisions that are actually yours are whether you count as a resident, and whether to elect the flat rate instead of the progressive scale - and the second one is worth real money in either direction.

Run both calculations rather than guessing. One of them is better for you and which depends entirely on your income and deductions.

Resident or not

The test turns on presence: spend 183 days or more in Korea in a tax year and you are generally treated as a resident.

	Taxed on
Resident	Korean income, and in principle worldwide income
Non-resident	Korean-source income only

Residency is about tax, not immigration, so you can be a tax resident on a short visa or a non-resident on a longer one. If you have income outside Korea, this is the point at which to take advice, because your home country's rules and any double tax treaty between the two interact here. Treaties also carry specific exemptions, including for some teachers and researchers for a defined initial period.

The year-end settlement

Employees go through a reconciliation early in the year following the tax year, comparing what was withheld against what you actually owe after deductions. Most people receive money back; some owe a little more.

Your employer runs it. Your job is to supply the evidence for your deductions by their deadline, and the tax authority's online service will have pulled most of it already from card companies, insurers and hospitals. Check what it has, and add what it has missed.

If you are not an employee, or you have other income, you file a return yourself later in the spring instead.

The flat rate, and when it wins

Foreign workers can elect a flat rate applied to gross employment income instead of the progressive scale, available for a defined period counted from when you first worked in Korea. Confirm the current rate and eligibility period before deciding, because both have been amended.

The trade is simple and absolute: the flat rate ignores deductions entirely. So it tends to win for higher earners with few deductions, and lose for people with substantial ones. The things that push you toward the progressive scale are a spouse and children, large medical or education costs, housing deductions, generous pension and insurance contributions, and heavy card spending.

Elect it through your employer at settlement time. Run the numbers both ways, every year, because your circumstances change.

Deductions worth knowing about

Even if you expect to take the flat rate, know what you would be giving up:

• National health insurance and pension contributions, which you are paying anyway. Health insurance enrolment covers the premiums.
• Credit and debit card spending above a threshold, which is the quiet reason Koreans put everything on a card. Banking covers getting one.
• Medical and education expenses, including for dependants.
• Dependants, where they qualify.
• Monthly rent, subject to conditions on income, the property and whether your lease and move-in are registered. Another reason to file that move-in report. Housing covers it.
• Pension and insurance products, and donations.

Some deductions are restricted or unavailable to non-residents, and a few are unavailable to foreign nationals specifically.

Other things that are taxed

Severance pay is taxed under its own rules rather than as ordinary salary, which generally works in your favour. Payment covers severance and the pension refund.

A local income tax is levied on top of your income tax as a proportion of it, so quoted headline rates are not the whole bill. Business income, rental income and capital gains each have their own treatment, and if you are self-employed or running a company the picture is different enough to warrant an accountant. Business is not the place for that; take professional advice.

Freelance and side income

If you are paid for independent work rather than as an employee, the mechanics differ. The payer typically withholds a small flat percentage at source and issues you a statement, and that withholding is a payment on account rather than a final settlement. You then reconcile it in a return you file yourself in the spring, which is often where a refund appears.

Two warnings. First, this is a tax question and a visa question at the same time: work outside what your status permits is a status problem no matter how the tax is handled, and a clean tax record does not legitimise it. Visa covers what each category allows.

Second, keep your own record of what you were paid and what was withheld. Payers vary in how reliably they issue statements, and without them the reconciliation is guesswork.

Leaving Korea mid-year

Do not simply fly out. Ask your employer for an early settlement with your final salary, so your tax position for the part-year is closed properly.

This matters because it is usually the point at which a refund is due, and because an unresolved tax position is exactly the kind of loose end that surfaces if you later return or apply for anything. Settle it alongside your pension refund question and your health insurance deregistration, as one exit checklist.

Where this goes wrong

• Never running the flat rate against the progressive scale. One is better; find out which.
• Missing your employer's settlement deadline and losing the deductions.
• Assuming the online service captured everything. Check it.
• Paying cash for everything and forfeiting the card deduction.
• Unfiled returns or arrears, which reappear at your visa extension.
• Leaving the country without an early settlement.

Where to go next

Payment covers severance and the pension lump sum, and visa extension covers why tax arrears matter to your stay.