Comprehensive Income Tax Calculator

Enter freelance or business revenue, expenses (simple or standard expense rate, or actual book expenses), personal deductions and National Pension contributions to get business income, tax base, computed tax, credits and local income tax under Korea's Income Tax Act, compared with the 3.3% already withheld to show a refund or an amount to pay.

2025 tax year (filed May 2026)

Revenue and expenses

2025 business revenue (KRW, before the 3.3% withholding)

How expenses are counted

Simple expense rate (%)

Excess rate (%) — revenue above KRW 40M

Personal-service freelancer (industry code starting 94: writers, instructors, designers etc.)The simple rate applies up to KRW 40 million of revenue; the excess rate applies above that (NTS Notice 2026-14, Art. 4).

Expense rates are set by the National Tax Service for each industry code and year. The defaults 64.1%, 49.7% and 17.4% are the 2025 rates for code 940909 ("other self-employed") in NTS Notice 2026-14. Other codes differ (e.g. 940100 writers: 58.7%, 42.2%, 7.2%), so look up your own code's 2025 rates on Hometax.

Industry and last year's revenue (which method)

Industry group

Last year's (2024) revenue

Started the business in 2025 Licensed professional (lawyer, tax accountant, doctor…)Always a double-entry filer regardless of revenue; the simple rate is not allowed.

Other income

Salary: total taxable pay (0 if none)

Employment income (gross pay minus the employment income deduction) is added in, with the employment income tax credit (55% of the tax on the salary share, 30% above KRW 1.3 million, capped at KRW 740,000 down to 200,000 depending on pay) and the KRW 130,000 standard credit. It assumes no employee itemised deductions, special credits (insurance, medical, education, donations, card spending) or rent credit. Put the income tax already withheld through year-end settlement in "Other income tax withheld" below.

Other income added in (excluding salary)

Enter income amounts, not gross receipts (interest, dividends, pensions or other income taxed together).

Income deductions

Basic deduction people (incl. you)

Aged 70+

Disabled

KRW 1.5 million per person. A spouse or dependant counts if their income is KRW 1 million or less (or salary only, up to KRW 5 million gross). Aged 70+ and disabled are counts among those people.

Women's deduction KRW 500,000Total income KRW 30 million or less, and a married woman, or an unmarried female head of household with dependants. Single-parent deduction KRW 1 millionNo spouse and a child who qualifies for the basic deduction. Replaces the women's deduction if both apply.

National Pension paid by you (year)

Yellow Umbrella mutual aid paid

National Pension is deducted in full. Yellow Umbrella limit by business income: up to KRW 40M → 6M, up to 60M → 5M, up to 100M → 4M, above → 2M.

Tax credits

Children aged 8+

Pension savings paid

IRP paid

Child credit (dependants aged 8+): 1 child KRW 250,000, 2 children 550,000, each extra child +400,000. Pension accounts: savings up to 6M, with IRP up to 9M; 15% if total income ≤ KRW 45M, else 12%. The standard credit is automatic (70,000 without salary, 120,000 for a diligent business).

Tax already paid

Income tax withheld at 3% (blank = revenue × 3%)

Local tax withheld at 0.3% (blank = 10% of the left)

Interim prepayment (November)

Other income tax withheld (salary etc.)

Annual withholding can be checked in your payment statements or on Hometax ("submitted payment statements").

Include the no-bookkeeping penalty for expense-rate filingSimple-book filer without books: computed tax × business share × 20%. Not applied to new businesses or if last year's revenue was under KRW 48 million.

Edit the rules 2025 tax year

Rates (tax-base band, rate %, quick deduction KRW)

Up to

Quick ded.

Up to

Quick ded.

Up to

Quick ded.

Up to

Quick ded.

Up to

Quick ded.

Up to

Quick ded.

Up to

Quick ded.

Above

Quick ded.

Simple-rate and simple-book thresholds (last year's revenue under, KRW)

Personal svc, simple

Personal svc, books

Farming/retail, simple

Farming/retail, books

Mfg/food…, simple

Mfg/food…, books

Rental/services, simple

Rental/services, books

Expense rates and penalty

Excess-rate threshold

Cap ratio (simple books)

Cap ratio (double entry)

Small business (last year under)

No-books penalty %

Personal deductions (KRW)

Basic (per person)

Aged 70+

Disabled

Women's

Women's: income cap

Single parent

Yellow Umbrella limit (business income band → limit)

Up to

Limit

Up to

Limit

Up to

Limit

Above

Limit

Tax credits

Bookkeeping credit %

Bookkeeping credit cap

1 child

2 children

Each child from 3rd

Pension savings cap

Total with IRP cap

Pension acct, lower income %

Pension acct, other %

Pension acct income line

Standard credit (salary)

Standard credit (diligent)

Standard credit (other)

Withholding, local tax, rounding

Withholding %

Local income tax %

Payment rounding unit

Defaults follow the rules for the 2025 tax year (filed May 2026): the Income Tax Act as in force in 2025 (effective 1 Jul 2025, Act No. 20615), its Enforcement Decree Art. 143 and 208, Enforcement Rule Art. 67, the Restriction of Special Taxation Act Art. 86-3 (amended 14 Mar 2025) and the National Tax Service's 2025 bookkeeping guide. Rates Art. 55; personal deductions Art. 50–51; pension contributions Art. 51-3; bookkeeping credit Art. 56-2; employment income credit Art. 59; child credit Art. 59-2 (age 8+ for 2025; amended on 21 Apr 2026 to 13+, phased in as 9+ for 2026, 10+ 2027, 11+ 2028, 12+ 2029); pension accounts Art. 59-3; standard credit Art. 59-4(9); no-books penalty Art. 81-5; 3% withholding Art. 129(1)3. The standard-rate cap ratio is a temporary rule through the 2027 tax year. Edit the numbers here if the law or the year changes.

0KRW

This is an estimate for reference. It follows Korea's Income Tax Act (2025 tax year) for a resident's business income (mainly freelancers) plus any other income you enter. This is not tax advice. The default expense rates are those for code 940909, so replace them with your own code's rates. Confirm the real amount on Hometax's filing screen, with the tax office or a tax accountant.

Included

Simple rate (excess rate above KRW 40M for personal services), standard rate (with the cap ratio) and books, plus which method and book type apply
Basic and additional personal deductions, National Pension, Yellow Umbrella, basic rates 6 to 45%
Employment income (from gross pay) and the employment income tax credit; bookkeeping, child, pension-account and standard credits; the no-books penalty, settling against the 3.3% withholding and interim prepayment, local income tax (10%)

Not included

Employees' itemised deductions and special credits (insurance, medical, education, donations, card spending), the rent credit
Financial-income comparison taxation, choosing separate taxation (home rental, other income, pensions), the birth/adoption credit
SME and start-up tax reliefs, the diligent-filing confirmation regime, joint businesses, property rental, loss carry-forward, annualising for new businesses, estimate filing by double-entry filers (non-filing penalty), and the simple-rate bars for not joining the cash-receipt system or repeatedly refusing card/cash receipts (Enforcement Decree Art. 143(7)3–4)

What this tool does

Estimates Korean comprehensive income tax for freelancers and sole proprietors for the 2025 tax year (filed in May 2026). It takes revenue minus expenses to get business income, subtracts personal deductions, National Pension and Yellow Umbrella payments to get the tax base, applies the basic rates, and takes off child, pension-account and standard credits to reach the tax determined and local income tax. It then compares that with the 3.3% already withheld (3% income tax + 0.3% local tax) to show a refund or an amount to pay. Expense rates, tax rates and deduction amounts can be edited under "Edit the rules".

How it is calculated

Expenses are counted one of three ways. The simple rate treats revenue × the simple expense rate as expenses (for personal services, the base rate up to KRW 40 million of revenue and a lower excess rate above it). The standard rate adds revenue × the standard rate to major expenses with receipts (purchases, rent, wages); double-entry filers use half the standard rate, and the result can be capped at simple-rate income × 2.8 (simple-book filers) or 3.4 (double-entry filers) through the 2027 tax year. With books you deduct actual expenses. The simple rate is only available if last year's revenue was under KRW 36 million (personal services, manufacturing, food), 60 million (farming, retail) or 24 million (rental and other services), and this year's revenue is under the simple-book line (75M / 300M / 150M / 75M). Rates run in 8 bands from 6% up to KRW 14 million of tax base to 45% above KRW 1 billion. Example (the page defaults): personal-service revenue KRW 30,000,000 with a 64.1% simple rate (the 2025 rate for code 940909) → expenses 19,230,000, business income 10,770,000. After the 1,500,000 basic deduction and 1,200,000 National Pension, the tax base is 8,070,000 and the computed tax 484,200 (6%); less the 70,000 standard credit, tax determined is 414,200 and local tax 41,420. With 900,000 and 90,000 already withheld, you get back 485,800 + 48,580 = KRW 534,380.

Business income = revenue − expenses (simple rate, standard rate or books)

Total income = business income + other income (e.g. employment income)

Tax base = total income − personal deductions (KRW 1.5M per person + additional) − Yellow Umbrella − pension contributions

Computed tax = tax base × rate − quick deduction (≤14M 6%; ≤50M 15% − 1.26M; ≤88M 24% − 5.76M; ≤150M 35% − 15.44M; ≤300M 38% − 19.94M; ≤500M 40% − 25.94M; ≤1B 42% − 35.94M; above 45% − 65.94M)

Tax determined = computed tax − employment income, bookkeeping, child, pension-account and standard credits (credits limited to the computed tax)

To pay or refund = tax determined (+ no-books penalty) − 3% withholding, interim prepayment etc. Local tax is 10% of that, less the 0.3% withheld

Things to know

Expense rates differ by industry code and year. The 64.1%, 49.7% and 17.4% here are the 2025 rates for code 940909 ("other self-employed") in NTS Notice 2026-14; other codes differ (e.g. 940100 writers: 58.7%, 42.2%, 7.2%). Look up your own code's simple, excess and standard rates on Hometax.

A simple-book filer who files on expense rates without books (simple or standard rate) pays a no-books penalty (computed tax × business share × 20%), unless they are a small business: started in 2025, had last-year revenue under KRW 48 million, or only have year-end-settled business income.

If a double-entry filer files on expense rates it counts as not filing, so in practice they must file from books. Lawyers, tax accountants, doctors and other licensed professionals are double-entry filers whatever their revenue.

National Pension paid as a regional member is fully deductible, but regional health insurance is not an income deduction; it is a business expense when you file from books.

If you also have a salary, enter the gross pay. Employment income (after its deduction) is added in, and the employment income tax credit takes 55% of the tax on the salary share (30% above KRW 1.3 million), capped at KRW 740,000 down to 200,000 depending on pay. Add the tax withheld through year-end settlement to tax already paid.

The child credit age line is 8 for the 2025 tax year. An amendment of 21 Apr 2026 (Act No. 21548) raised it to 13, phased in as 9 for 2026, 10 for 2027, 11 for 2028 and 12 for 2029 (children born in 2017 are carved out of the phase-in). The birth/adoption credit is not included.

The 2025 filing deadline was 1 June 2026. You can still file late to claim a refund, or request a correction within 5 years if you already filed.

Frequently asked questions

Why do freelancers who had 3.3% withheld get money back in May?

The 3.3% is taken from your gross pay before any expenses or deductions. When you file in May the real tax is worked out after expenses and deductions and is usually lower, so the difference is refunded. With KRW 30 million of revenue and a 64.1% simple rate (code 940909), the tax determined is 414,200, so 485,800 of the 900,000 withheld comes back, plus 48,580 of local tax. With high revenue or other income you may owe more instead.

How is it decided whether I use the simple or standard rate?

By last year's revenue and your industry. For personal services (industry codes starting with 94) you may use the simple rate if last year's revenue was under KRW 36 million and this year's is under 75 million; otherwise you file on the standard rate or from books. If you started in 2025, the simple rate applies when this year's revenue is under the simple-book line. Licensed professionals cannot use the simple rate.

What is the excess rate?

For personal-service businesses using the simple rate, the base simple rate applies up to KRW 40 million of revenue and a lower excess rate applies to the part above it (NTS Notice 2026-14, Art. 4). The excess rate is listed next to each industry code in the rate table on Hometax.

Does keeping books lower the tax?

Yes, if your real expenses are higher than the expenses the rates allow. A simple-book filer who keeps double-entry books also gets a bookkeeping credit of 20% of the tax on business income (up to KRW 1 million), and regional health insurance can be counted as an expense.

Revenue and expenses

Industry and last year's revenue (which method)

Other income

Income deductions

Tax credits

Tax already paid

What this tool does

How it is calculated

Things to know

Frequently asked questions

References