# Comprehensive Income Tax Calculator

> Calculate Korean comprehensive income tax with 8-tier progressive rates and bracket visualization for self-employed and freelancers.

## What is this calculator?

The Comprehensive Income Tax Calculator helps self-employed individuals, freelancers, and sole proprietors in South Korea estimate their annual income tax liability. In Korea, comprehensive income tax (종합소득세) is filed annually in May and covers all types of income including business income, interest, dividends, rental income, pension, and other income.

Unlike salaried employees who settle taxes through year-end settlement (연말정산), self-employed individuals and freelancers must file their own comprehensive income tax return. This calculator applies Korea's 8-tier progressive tax rates (6% to 45%) to your taxable income after deducting business expenses and personal allowances.

The calculator also visualizes the tax amount for each bracket in a bar chart, helping you understand how progressive taxation works — only the income within each bracket is taxed at that bracket's rate, not your entire income.

## How to use

Step 1: Choose your expense input method.
• Direct Input: Enter your actual business expenses if you maintain bookkeeping records.
• Simple Expense Rate: Enter your industry's standard expense rate (%) if you do not keep detailed records. The calculator will automatically compute expenses as a percentage of revenue.

Step 2: Enter your total annual revenue (gross income from business or freelance work).

Step 3: Enter deduction items.
• Dependents: Number of dependents excluding yourself (1.5M KRW per person)
• National Pension & Health Insurance: Enter the full amount paid (fully deductible)
• Other Deductions: Any additional income deductions

Step 4: Enter tax credit items.
• Child Tax Credit: 150K for 1 child, 350K for 2, 350K + 300K per additional child
• If no children, the standard tax credit of 70K KRW is automatically applied

Step 5: Enter any prepaid tax (interim payments, withholding tax) to see your refund or additional payment amount.

## How it's calculated

The comprehensive income tax follows this calculation flow:

Total Revenue - Necessary Expenses = Total Income
Total Income - Deductions = Tax Base
Tax Base × Progressive Rate = Calculated Tax
Calculated Tax - Tax Credits = Final Tax
Final Tax + Local Tax (10%) = Total Tax Due

Progressive Tax Rates (8 tiers):
• Up to 14M: 6%
• 14M-50M: 15% (progressive deduction: 1.26M)
• 50M-88M: 24% (progressive deduction: 5.76M)
• 88M-150M: 35% (progressive deduction: 15.44M)
• 150M-300M: 38% (progressive deduction: 19.94M)
• 300M-500M: 40% (progressive deduction: 25.94M)
• 500M-1B: 42% (progressive deduction: 35.94M)
• Over 1B: 45% (progressive deduction: 65.94M)

Deductions:
• Personal Exemption: (dependents + 1) × 1,500,000 KRW
• National Pension: full amount paid
• Health Insurance: full amount paid

Tax Credits:
• Child Credit: 150K (1 child), 350K (2), 350K + 300K × (n-2) for 3+
• Standard Credit: 70K KRW (when no child credit applies)

## Useful tips

1. Bookkeeping Matters: Maintaining proper business records (bookkeeping) typically results in higher expense deductions than using the simplified expense rate. If your revenue exceeds certain thresholds by industry, you are required to use double-entry bookkeeping — consider hiring a tax accountant.

2. Simple vs Standard Expense Rate: If your previous year's revenue is below the threshold for your industry, you can use the simple expense rate (단순경비율). Above the threshold, you must use the standard expense rate (기준경비율), which is significantly lower — you'll need to provide documentation for major expenses (purchases, rent, labor) to reduce your tax base.

3. Interim Tax Payments: If you made interim tax payments in November, include them as prepaid tax to see your actual additional payment or refund amount.

4. Filing Deadline: The comprehensive income tax filing period is May 1-31 each year. Taxpayers subject to the faithful reporting system have an extended deadline until June 30.

5. Multiple Income Sources: If you have both employment income and business/freelance income, you must file comprehensive income tax combining all sources. Your employment income (already settled via year-end settlement) should be included in your total income calculation.

## FAQ

### Q. Who needs to file comprehensive income tax?

Comprehensive income tax filing is required for: individuals with business income (self-employed, freelancers, rental income), employees earning income from two or more employers, individuals whose financial income (interest + dividends) exceeds 20 million KRW annually, and individuals with other income exceeding 3 million KRW annually. Salaried employees with only one employer who completed year-end settlement do not need to file separately.

### Q. How do I find my simple expense rate?

Simple expense rates are published by the National Tax Service (NTS) and vary by industry code. For example, freelancers (code 940909) have a rate of 64.1%, restaurants (552101) have 89.7%, and so on. You can look up your specific rate on the Hometax website. If your previous year's revenue exceeds the threshold for your industry (e.g., 24M KRW for service businesses), you must use the standard expense rate instead, which is significantly lower and requires expense documentation.

### Q. What is the difference between comprehensive income tax and year-end settlement?

Year-end settlement (연말정산) is for salaried employees only — employers handle the tax reconciliation process in January-February. Comprehensive income tax (종합소득세) is for individuals with non-employment income (business, freelance, rental, etc.) who must file their own return in May. If a salaried employee also has side business income or financial income exceeding certain thresholds, they must file comprehensive income tax combining all income sources.

### Q. What are some ways to reduce comprehensive income tax?

Key tax-saving strategies include the Small Business Mutual Aid (Noranusangongje, up to 5M KRW income deduction), full deduction for National Pension and Health Insurance premiums, donation tax credits (15-30%), and pension savings/IRP tax credits (up to 9M KRW limit per year). For business owners, maintaining thorough bookkeeping records to maximize legitimate expense deductions is essential. The Small Business Mutual Aid also serves as a retirement safety net in case of business closure, making it particularly valuable for self-employed individuals.

### Q. When is the filing period and how do I pay?

The comprehensive income tax filing period runs from May 1 to May 31 each year. Taxpayers subject to the faithful reporting confirmation system receive an extension until June 30. You can file through the National Tax Service's Hometax portal (www.hometax.go.kr), the mobile Sontax app, or by visiting your local tax office in person. If your tax due exceeds 10 million KRW, you may pay in installments within two months. Missing the deadline results in a non-filing penalty (20% of tax due) and a late payment surcharge (0.022% per day), so timely filing and payment are critical.