Korean Freelancer Income Tax Return Calculator
What a freelancer gets back, or owes, in May. Compares the 3.3% withheld through the year against the tax actually due.
3% is a prepayment, not the tax
Your income
Expense rates differ by trade. The tax office publishes a simplified rate and a standard rate for each business code, and they change every year. Look up the rate for your own code on Hometax and enter it. If you keep books, use your actual expenses rather than a rate.
When you settle in May
You get ₩297,000 back. ₩990,000 was withheld over the year against a real liability of ₩693,000.
Tax due
₩693,000
2.31% effective · local tax included
Already paid
₩990,000
3% withholding + local tax
Refund
₩297,000
comes back to you
| Revenue | ₩30M |
|---|---|
| Necessary expenses (60%) | − ₩18M |
| Business income | ₩12M |
| Basic deduction (1 × ₩1.5M) | − ₩1.5M |
| Other deductions | − ₩0 |
| Tax base | ₩10.5M |
| Computed tax (6%) | ₩630,000 |
| Local income tax | ₩63,000 |
| Total tax | ₩693,000 |
| Already paid | − ₩990,000 |
| Refund | ₩297,000 |
The basic deduction is ₩1.5M a year per person (소득세법 제50조제1항). Dependants have to meet conditions such as income of ₩1M or less. This calculator assumes business income only. If you also have employment or rental income, everything is combined and taxed at progressive rates, which raises the bill. Tax credits (children, pension accounts, donations) and penalty taxes are not included.
How this works
What it calculates
When a freelancer or sole trader in Korea is paid, 3.3% is withheld, but that is a prepayment, not the final tax. The real tax only emerges once a year's revenue has expenses and deductions taken off and the progressive rates applied, and the difference between that and what was prepaid is settled in the May global income tax return the following year. Enter annual revenue, your industry's expense ratio, the number of people for the basic deduction, other deductions, and the income tax already withheld, and this calculator tells you whether May brings a refund or a bill, and how much.
The expense ratio is not supplied for you. The simplified and standard expense ratios are published by the National Tax Service for each industry code and change every year, so any default baked in here would be wrong for someone from the day it was set. Look up the ratio for your own code on Hometax, and if you keep books, use your actual expenses instead.
Who uses it and when
Anyone paid with 3.3% withheld: designers, developers, tutors, delivery riders, insurance agents, and everyone else paid for work without being on a payroll. People with modest income usually end up with a refund, and many never file because they do not know that. Running your own numbers before May makes the reason to file obvious.
At the other end, someone with high revenue and low expenses will owe more, and needs the figure in advance to have the cash ready in May. If you have room to increase deductions, through national pension contributions or the Noran Umbrella mutual aid scheme for example, the calculator also helps decide how much to put in before year end.
Legal basis and how the maths runs
Withholding is set by 소득세법 제129조제1항제3호 at 3% of business income paid, and 10% local income tax on top makes it 3.3%. The annual return is filed in May under 제70조. The basic deduction under 제50조제1항 is ₩1,500,000 per person a year, and the rates come from the 8-bracket progressive schedule in 제55조제1항, starting at 6% on a tax base up to ₩14,000,000 and rising to 45% at the top.
There are five steps. Revenue less expenses (revenue times the expense ratio) gives business income; less the basic deduction and other deductions gives the tax base. The tax base times the bracket rate, less the progressive deduction, gives the calculated tax, and 10% of that is added as local income tax to give the total. Finally, the tax already withheld, plus its local income tax, is subtracted: a positive remainder is a bill, a negative one is a refund. If you leave the withheld amount blank, the calculator assumes 3% of revenue.
A worked example
Take a freelancer with ₩30 million of annual revenue, an industry expense ratio of 60%, and no dependants. Expenses are 60% of ₩30 million, or ₩18 million, leaving business income of ₩12 million. After the ₩1,500,000 basic deduction the tax base is ₩10.5 million, which falls in the lowest bracket at 6%. The calculated tax is ₩630,000, plus ₩63,000 local income tax, for a total of ₩693,000.
But 3% of ₩30 million, or ₩900,000, was withheld during the year, and with local income tax that is ₩990,000 already paid. That is ₩297,000 more than the actual tax, so filing in May returns that amount. Skip the filing and the money stays with the tax office.
Common mistakes
The most common is treating the 3.3% as the end of the matter and skipping the May return. For low earners that means giving up a refund; for high earners it means a penalty for non-filing. The second is entering the full 3.3% in the "income tax already withheld" field. That field takes the 3% income tax only; the calculator adds the local income tax itself, so entering the whole amount inflates the prepayment and overstates the refund.
The third is borrowing someone else's expense ratio. Ratios differ by industry code, and whether you may use the simplified ratio or must use the standard one depends on your revenue. The fourth is leaving out other income. This calculator assumes business income is your only income; if you also have employment or rental income, everything is aggregated under the progressive rates and the tax rises. Tax credits for children, pension accounts and donations, and any penalties, are not included, so the result will differ if those apply.
The order of calculation
- 1Revenue − necessary expenses = business income
- 2Business income − basic deduction (₩1.5M each) − other deductions = tax base
- 3Tax base × ordinary rates = computed tax
- 4Computed tax + 10% local income tax = total tax
- 5Total tax − the 3.3% already withheld = refund or amount owed
Global income tax rates
| Tax base | Rate | Progressive deduction |
|---|---|---|
| Up to ₩14M | 6% | — |
| Over ₩14M, up to ₩50M | 15% | ₩1.26M |
| Over ₩50M, up to ₩88M | 24% | ₩5.76M |
| Over ₩88M, up to ₩150M | 35% | ₩15.44M |
| Over ₩150M, up to ₩300M | 38% | ₩19.94M |
| Over ₩300M, up to ₩500M | 40% | ₩25.94M |
| Over ₩500M, up to ₩1B | 42% | ₩35.94M |
| Over ₩1B | 45% | ₩65.94M |
The rates are in 소득세법 제55조제1항. Capital gains tax and retirement income tax use the same table.
About this calculator
When to use it
Use this if you were paid as a freelancer with 3.3% withheld. A global income tax return Korea filing in May recalculates the tax at the real progressive rate, so the withheld amount often comes back as a refund.
What it calculates
Your May tax return, with expenses and withholding already paid.
Last updated . Found something wrong? Tell us.
Common questions
- 3% was already withheld, so why file at all?
- Because 3% is money paid in advance, not the tax itself. The real liability is only settled once expenses and deductions come off a full year of revenue. Filing in May settles the difference, and on a modest income that usually means a refund.
- Where do I find my expense rate?
- The tax office publishes a simplified rate and a standard rate for every business code. Look yours up on Hometax. They change annually, which is why this calculator does not fill in a figure for you. If you keep books, use actual expenses instead.
- What is the difference between the simplified rate and the standard rate?
- Small businesses with modest revenue use the simplified rate, which treats most of the revenue as expenses. Above a certain size you move to the standard rate, where major costs such as wages and rent are only allowed with documentation and the rest is estimated by rate. The same revenue can produce very different tax.
- When does the refund arrive?
- Usually June or July if you file in May. The deadline is 31 May of the following year, or 30 June for those subject to faithful-filing confirmation.
- What if I also have employment income?
- It is combined. Freelancing alongside a job means both incomes are added and taxed at progressive rates, which raises the bill. This calculator assumes business income only, so it will understate that case.
- Do foreign freelancers file in May?
- If you are a tax resident, you file exactly as a Korean national would. 소득세법 attaches no nationality requirement. Non-residents file only on Korean-source business income, and any tax treaty takes precedence. If you have to leave Korea before the deadline, file by the day before departure or appoint a tax manager.
Paid by the day? See what is withheld
Explainers that cover this
The assumptions and the statutes behind them, written out.
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Proposed changes that touch this calculation
The 2026 tax reform bill has 2 items bearing on this calculation, the earliest from 2027-01-01. None of it has passed the National Assembly, so the calculator still applies the law as it stands.
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