Korea tax guide
Global Income Tax Filing: Preparation and Submission Checklist
Income Tax
Who this guide is for
- Foreigners who have confirmed they need a comprehensive income tax return
- Freelancers preparing payer and expense records
- Employees combining salary and other reportable income
- Filers checking that both national and local tax steps are complete
Quick Answer
After confirming your filing obligation, build one record for the correct income year: income by category, support for expenses and deductions, and tax already paid. Reconcile it with payer statements and Hometax before submitting. Save the national return acceptance and payment record, then complete and retain the separate local income tax filing and payment records where applicable. A draft refund estimate is not proof of a completed return or payment.
Key points
- Use the filing-obligation guide first if you do not yet know whether a return is needed.
- Reconcile gross income, net deposits, and withholding as separate figures.
- Income deductions, tax credits, and tax already paid affect different calculation stages.
- National filing, local filing, and payment each need their own completion evidence.
Detailed explanation
Build a filing record after confirming the obligation
This page focuses on preparing and closing a return. If you are still deciding whether employer settlement was enough, start with the filing-obligation guide. If you need help locating filing screens, use the Hometax procedure.
The name “Global Income Tax” is commonly used for 종합소득세, comprehensive income tax. Do not use that English name to decide whether every foreign income item belongs in your return. Resolve the income scope before preparing the calculation.
1. Set the income year and filing route
Write the income year at the top of the worksheet and document folder. Also record whether you are preparing an original return, late return, amended return, or refund claim. Check previous submissions for that year so that you do not create duplicate records or choose a correction route intended for a different problem.
Review the current official deadline for the category and year. The NTS filing-period table distinguishes ordinary annual filing from the professional-review category. A special payment extension should not be assumed to extend the filing deadline.
2. Reconcile each payer before calculating tax
Create one row for each income source. Compare your own evidence with the payer statements and records available in Hometax.
| Worksheet field | Supporting record | Discrepancy to investigate |
|---|---|---|
| Payer and income category | Contract, withholding statement, payment statement | Payer name, missing payer, or wrong category |
| Gross payment or receipts | Invoice, payroll record, sales or payment ledger | Net deposit mistaken for gross income |
| Tax withheld | Statement separating the relevant tax amounts | A combined national/local amount copied into one national field |
| Expenses where relevant | Ledger and evidence for each claimed cost | Personal cost, duplicate cost, or unsupported estimate |
| Salary already settled | Final employer receipt and settlement result | Earlier employer omitted or the same salary entered twice |
| Other tax already paid | Official prepayment/payment record | Tax type, year, or payer mismatch |
If the numbers differ, keep a separate explanation rather than overwriting the source documents. A bank deposit can reflect withholding or fees; an income amount can reflect category-specific deductions. Compare the same measure before calling a difference an error.
For example, if a statement shows a gross client payment and a smaller deposit, record the two figures separately and identify the difference from the actual statement. Do not assume that every difference is tax or treat every deposit as new income.
3. Keep the calculation stages separate
The NTS calculation flow separates income amounts, income deductions, the tax base, calculated tax, credits and reductions, penalties, and tax already paid. Your supporting records should make those stages traceable.
| Stage | Preparation question |
|---|---|
| Income by category | Have the correct category rules and any relevant income adjustments been applied? |
| Income deductions | Is each deduction eligible and supported for this taxpayer and year? |
| Calculated tax | Is the correct method being applied to the tax base? |
| Tax credits and reductions | Does the evidence establish eligibility, limits, and any required application? |
| Tax already paid | Are withholding and prepayments matched to the same person, tax, and year? |
| Balance or refund | Can the result be traced back to the completed calculation? |
For business income, the NTS overview describes income calculated from books as receipts less necessary expenses, and separately explains estimated-expense methods. Do not select an expense ratio because it produces a preferred refund. Confirm eligibility and the required records; use the bookkeeping guide for preparation questions.
A simplified reconciliation example: suppose the completed national calculation gives tax of KRW 900,000 before subtracting already-paid tax, there are no additional adjustments, and eligible national tax already paid is KRW 1,200,000. The difference is a KRW 300,000 refund. This illustrates subtraction only: it does not estimate anyone’s tax, establish deduction eligibility, or calculate local income tax.
4. Review the return as a whole
Before submission, check the income year, taxpayer details, every income category, business figures where relevant, deductions and credits, tax already paid, attachments, and bank details requested by the portal. Compare the return with the worksheet rather than relying only on the final payment or refund figure.
If a prepared draft omits an income source, investigate it even when the draft appears ready to submit. If residence, treaty treatment, foreign tax credits, or the accounting method remains unresolved, take the worksheet and the specific question to the NTS or a qualified adviser before making an unsupported selection.
5. Close national and local filing separately
After national submission, save the acceptance receipt and final return. Record the payment deadline and verify any national payment through its completed result.
The NTS local-income-tax instructions describe moving from Hometax to Wetax after national filing, then preparing and submitting the local return. Follow through to its completion; a navigation link is not a local submission receipt. See the local income tax guide for the distinction.
| Completion record | What to retain |
|---|---|
| National return | Final copy, acceptance receipt, attachments where required |
| National payment or refund details | Payment result if due, or submitted refund details and later status |
| Local return | Final copy and separate acceptance receipt |
| Local payment or refund details | Separate payment result if due, or refund details/status |
| Reconciliation record | Worksheet, payer statements, and explanations for resolved differences |
A return can be accepted before an amount due has been paid. Likewise, a refund shown on a submitted return is not evidence that it has reached the bank. Use the refund-status procedure for follow-up and keep any later correction tied to the same income-year folder.
Documents you may need
- Income-year worksheet with every reportable payer and category
- Wage settlement and income withholding statements
- Business ledger and supporting expense records where applicable
- Evidence for deductions, credits, foreign tax, and prepayments claimed
- National and local submission receipts, payment results, and final return copies
Common mistakes
- Entering net bank deposits as gross income
- Deducting withholding as a business expense
- Claiming the same payment or credit twice
- Assuming a Hometax draft contains every income item
- Leaving after national submission without checking local filing and payment
When should you ask a tax professional?
Ask a qualified tax professional if you have income from several countries, business income, unclear tax residency, treaty questions, missing documents, late filing concerns, or a visa situation that depends on tax records. This site explains general patterns only and cannot review your personal facts.
FAQ
Is this the guide for deciding whether I must file?
This page begins after that decision. Use the Korea income tax filing guide first to check employer settlement, income categories, and residence questions.
Should I enter the amount deposited in my bank account?
Reconcile the gross payment, withholding, fees, reimbursements, and net deposit first. The bank deposit alone may not be the income figure the return requires.
Where does tax already withheld enter the calculation?
The NTS calculation flow deducts tax already paid, including withholding, after the relevant tax calculation, credits, reductions, and penalties. Keep it separate from business expenses and personal deductions.
Does submitting national income tax also complete local income tax?
Check the local return separately. The NTS describes a Hometax-to-Wetax link after national submission, followed by preparation and submission of the local return. Keep both receipts and check both payment results.
Does an estimated refund mean filing is finished?
No. Confirm return acceptance, the final submitted amounts, any required attachments, local filing, and payment or refund details. A saved draft or preview does not establish completion.
Official Sources to Verify
Check the tax year, eligibility conditions, and publication date in the official material before applying a rule. A link marked “Service portal” helps you find a service; it does not substantiate a particular rate or entitlement.