Filing your May tax return in Korea as a foreigner: the complete 2026 step-by-step guide
Every May, the same wave of panic hits expat group chats across Korea. "Do I need to file?" "I thought my company already did my taxes?" "If I just ignore it, will they notice?" The answers are yes, maybe, and absolutely — they will notice. The National Tax Service (NTS) → cross-references every payment ever made under your ARC number. There is no hiding.
📌 This article provides general information based on official published data. Always consult a qualified financial advisor or licensed tax accountant (세무사) before making tax filing decisions.
Having walked through this process with dozens of expats — engineers, YouTubers, English teachers, startup founders — I can tell you the single biggest mistake foreigners make is assuming their situation doesn't require a May filing. The Jonghap Sodeukse (종합소득세 — comprehensive income tax) deadline falls on May 31, 2026, and the penalties for getting it wrong are steep. This guide is your decision tree: who files, who doesn't, and the exact Hometax clicks to finish it in under 30 minutes.
🟢 NO filing needed — Single employer, year-end settlement (연말정산) completed in Jan/Feb, no other income
🔴 YES, file by May 31 — Freelancer (3.3% withholding), dual-income, rental/dividend income, missed year-end settlement, departing Korea permanently
🟡 Optional but recommended — You missed deductions during year-end settlement (medical, education, donations) and want to claim them retroactively
Who exactly must file the May comprehensive income tax return?
Anyone with untaxed or partially-taxed income from 2025 must file between May 1 and May 31, 2026. The Comprehensive Income Tax combines every income stream — salary, freelance, rental, dividends, pensions, and capital gains — into a single consolidated return. Think of the year-end settlement as a "preview" and the May filing as the "final exam."
The confusion stems from Korea's dual-track system. Regular employees on the 4-major-insurance package get their taxes reconciled automatically through Yeonmal Jeongsan (연말정산 — year-end tax settlement) every January. Your HR department handles it, you submit receipts, and it's done. But the moment your income picture gets even slightly complicated, that automatic process is no longer sufficient.
Here are the five scenarios that trigger a mandatory May filing for foreigners:
One edge case that surprises many: if you're a salaried employee but also received financial income (interest + dividends) exceeding ₩20 million in 2025, you are required to add that to your comprehensive return. Your employer's year-end settlement doesn't capture this stream — you must report it yourself in May.
The 2026 progressive tax brackets at a glance
Korea uses an 8-bracket progressive system ranging from 6% to 45%, plus a 10% local income tax surcharge. Understanding where your taxable income lands determines whether you owe additional tax or get a refund in May.
| Taxable Income (Annual) | National Tax Rate | Effective Rate (incl. Local Tax) |
|---|---|---|
| Up to ₩14,000,000 | 6% | 6.6% |
| ₩14M – ₩50,000,000 | 15% | 16.5% |
| ₩50M – ₩88,000,000 | 24% | 26.4% |
| ₩88M – ₩150,000,000 | 35% | 38.5% |
| ₩150M – ₩300,000,000 | 38% | 41.8% |
| ₩300M – ₩500,000,000 | 40% | 44% |
| ₩500M – ₩1,000,000,000 | 42% | 46.2% |
| Over ₩1 Billion | 45% | 49.5% |
Let's run a real scenario. Say you're an E-7 visa holder with a ₩60,000,000 annual salary, and you picked up ₩8,000,000 in freelance consulting on the side during 2025. Your employer already settled tax on the ₩60M through year-end settlement. But that ₩8M freelance income — where clients withheld 3.3% (₩264,000) — remains unsettled. In May, you must consolidate both streams. With your combined ₩68M taxable base, you're now in the 24% bracket. The additional tax on the freelance portion, after deducting the Dansun Gyeongbiryul (단순경비율 — simple expense ratio) and the ₩264,000 already withheld, could mean either a small additional payment or a refund depending on your deductions.
"Foreigners who reside in Korea for 183 days or more are considered tax residents and must report worldwide income. Those staying under 183 days report only Korean-sourced income." — National Tax Service Foreign Taxpayer Guidelines, April 2026.
A critical detail many expats miss: the 183-day residency rule changed subtly in recent years. If you've accumulated 183 days across two consecutive tax years (not just within a single year), the NTS may classify you as a tax resident. This triggers worldwide income reporting obligations — meaning overseas dividends, foreign rental income, and even crypto gains from platforms outside Korea become reportable.
The 19% flat tax rate: should you elect it?
Eligible foreign workers can choose a flat 19% rate (20.9% with local surtax) instead of progressive brackets — but it's only beneficial for high earners above roughly ₩130M. This is formally called the Teukbyeol Segam (특별세감 — special tax reduction) under the Restriction of Special Taxation Act. It's available for up to 20 years from your first working day in Korea (as of 2026), but there's a major catch: you forfeit virtually all itemized deductions.
I've run the numbers on this myself — the crossover point where 19% flat beats the progressive system typically sits around ₩120M to ₩150M gross annual salary. Below that range, the standard progressive rate with basic personal deductions (₩1.5M per taxpayer), national pension deductions, and health insurance deductions will almost always result in a lower effective tax rate. If you earn ₩70M and elect 19% flat, you'd pay roughly ₩14.6M in tax. Under the progressive system with deductions, your liability would be closer to ₩9M — a ₩5.6M difference. That's not a rounding error; that's a vacation fund.
To elect the flat rate, you must declare your choice on your tax return. This can be done during the year-end settlement period or during the May filing on Hometax. Once elected for a given tax year, you cannot switch back to progressive for that same year.
Step-by-step: how to file on Hometax as a foreigner
The entire process takes 15–30 minutes if your income is straightforward. Here is the exact workflow on the Hometax portal → as of 2026, translated and annotated for non-Korean speakers.
Before you start, you'll need your ARC number, a registered authentication method (KakaoTalk, Naver, Toss, PASS, or a bank-issued certificate), and your Korean bank account number for refunds. If you've never registered on Hometax before, you'll need to create an account first using your ARC — the system accepts registration by Alien Registration Number (외국인등록번호).
Step 1 — Login: Go to hometax.go.kr. Click 간편인증 (Simple Authentication). Enter your name exactly as it appears on your ARC (ALL CAPS, surname first). Enter your 13-digit ARC number. Choose your authentication app (Kakao is easiest). Complete verification on your phone.
Step 2 — Navigate: During May, Hometax displays a giant popup for 종합소득세 신고. Click it. Alternatively: Menu → 세금신고 → 종합소득세 신고 → 정기신고 (Regular Filing).
Step 3 — Check your filing type: The system will show your Singoyuhyeong (신고유형 — filing type). Look for 모두채움 (Pre-filled) — this means the NTS has already calculated everything for you. Simply review and submit. If you see 일반신고 (Regular Filing), you'll need to manually enter income details.
Step 4 — Income retrieval: Click 소득 불러오기 (Retrieve Income). The system pulls every payment registered under your ARC — salary income from employers, 3.3% freelance payments, interest, dividends. Cross-check against your own records.
Step 5 — Deductions: Enter applicable deductions — basic personal deduction (₩1.5M), dependents, NPS contributions, health insurance premiums, and any additional expenses. For freelancers, select either 단순경비율 (Simple Expense Ratio) or 기준경비율 (Standard Expense Ratio) depending on your income level.
Step 6 — Review and submit: Verify the calculated tax amount. If you owe, you'll see 납부 (Payment). If the government owes you, you'll see 환급 (Refund). Input your Korean bank account for refunds. Click 신고서 제출 (Submit Return).
Step 7 — Wetax (local tax): After submission, Hometax redirects you to Wetax → to file and pay the 10% local income tax surcharge. This is mandatory — don't skip it.
One tip that saves time: the SonTax (손택스) mobile app mirrors the full Hometax functionality. If your income is simple (one employer + some 3.3% side income) and the NTS shows you as a 모두채움 (pre-filled) filer, you can literally complete the entire filing on the subway. I've done it — three taps, review the number, submit. Done before the next station.
Understanding expense ratios: the secret to maximizing your refund
Freelancers with income under roughly ₩24M qualify for the generous Dansun Gyeongbiryul (단순경비율 — simple expense ratio), which deducts 40–80% of gross income as assumed business expenses. This is the mechanism that generates those surprisingly large refund checks in June.
The Korean tax system acknowledges that freelancers and sole proprietors incur business costs. Rather than requiring every receipt, the NTS assigns a Gyeongbiryul (경비율 — expense ratio) based on your registered business code. For example, a freelance translator (code 940909) might receive a simple expense ratio of around 64.1%. That means on ₩20,000,000 gross income, the NTS assumes ₩12,820,000 in business expenses. You're only taxed on the remaining ₩7,180,000.
With that ₩7.18M taxable base falling in the 6% bracket, your national tax is roughly ₩430,800. But your clients already withheld ₩660,000 at 3.3% throughout the year. The math is clear: you're owed a refund of approximately ₩229,200. And that's before any additional personal deductions.
| Previous Year Income | Expense Ratio Type | Typical Deduction Range | Accountant Needed? |
|---|---|---|---|
| Under ~₩24M | 단순경비율 (Simple) | 40–80% auto-deducted | No — self-file via 모두채움 |
| ₩24M – ₩75M | 기준경비율 (Standard) | Major costs + small % | Recommended (₩150K–300K) |
| Over ₩75M | 복식부기 (Double-entry) | Full receipt-based ledger | Mandatory — do not DIY |
When your freelance income crosses the ₩24M threshold (using the previous year's revenue as the benchmark), you're bumped from 단순경비율 to 기준경비율 (Gijun Gyeongbiryul — standard expense ratio). This is a dramatically different calculation. Under the standard ratio, only your "major expenses" — rent, subcontractor fees, material costs — are deductible with receipts. The remaining expenses are covered by a much smaller automatic percentage. This is the income level where hiring a Semusa (세무사 — licensed tax accountant) for ₩150,000 to ₩300,000 almost always saves you more than it costs.
Penalties for missing the May 31 deadline
Miss the deadline and the NTS hits you with a 20% non-filing penalty plus 0.022% daily interest — and your visa renewal could be blocked. That's not hypothetical. The Musingoui Gasanse (무신고 가산세 — non-filing additional tax) applies immediately on June 1 if you haven't submitted.
Let's say your unpaid tax liability is ₩2,000,000. The non-filing penalty alone adds ₩400,000 instantly. Then the Napbu Buseongsilgasanse (납부불성실가산세 — delinquent payment surcharge) of 0.022% per day starts accruing. After 100 days, that's another ₩44,000. After a year, roughly ₩160,600 more. And here's the part that truly stings: unresolved tax debt blocks your visa extension application. Immigration requires a Napsejeungmyeong (납세증명 — tax clearance certificate) for most visa renewals and status changes. Unpaid taxes = no certificate = visa complications.
📌 Original tax owed: ₩2,000,000
📌 Non-filing penalty (20%): +₩400,000
📌 Daily surcharge (0.022% × 180 days): +₩79,200
📌 Total after 6 months: ₩2,479,200 — a 24% markup just for procrastination
The good news: if you missed last year's filing, you can still submit a Gihan Hu Singo (기한 후 신고 — post-deadline return) on Hometax. You'll face the penalty surcharges, but this is vastly better than not filing at all. And if the NTS owed you a refund, you can retroactively claim overpaid taxes for up to 5 years.
Special case: leaving Korea permanently
If you're departing Korea for good, you cannot wait for May. Under the Income Tax Act, you must file a Chulguk Singo (출국 신고 — departure filing) covering January 1 to your departure date. This must be done before you leave the country, because once your ARC is cancelled, accessing Hometax and Korean banking becomes significantly harder.
The practical approach: file your departure return at your local Semuseo (세무서 — district tax office) in person. Bring your ARC, passport, your employer's year-end settlement receipt (원천징수영수증), and your bank account details. If your departure falls between January and April, you'll file for a partial year. If it's after May, you should have already filed the regular comprehensive return for the previous year — make sure both are complete.
Frequently asked questions
Can I file my May tax return in English on Hometax?
No, the Hometax interface is entirely in Korean — but you can use Chrome's built-in translation to navigate effectively. The NTS does operate an English-language help desk at 1588-0560 (select option 7, then 1 for English). Agents can walk you through the filing process by phone during weekday business hours (9:00 AM – 6:00 PM). The mobile SonTax app also works with browser-level translation on most smartphones.
What happens if my employer filed my year-end settlement incorrectly?
You can correct it through the May comprehensive filing. Hometax allows you to override or supplement year-end settlement data during the May return. If your employer didn't include all your deductions (medical expenses, education costs, donation receipts), you can add them here to claim a refund on the difference. This is called Gyeongjeongseonggocheong (경정청구 — correction request), and it's available for up to 5 years.
I earn income from my home country while living in Korea — do I report it?
If you've been a Korean tax resident for 5+ years within the past 10 years, yes — worldwide income is reportable. However, Korea has double taxation agreements (이중과세방지협정) with over 90 countries. If you've already paid tax on that income in your home country, you can claim a Oegugnap Buseaek Gongjje (외국납부세액공제 — foreign tax credit) on your Korean return. This prevents paying full tax twice on the same income. Keep proof of the foreign tax payment — you'll need it.
Is there a penalty for filing but owing nothing?
No penalty if your calculated tax is zero or results in a refund. Even if your income was minimal, filing a zero-return secures your standing with the NTS and generates the tax clearance certificate you may need for visa renewals. There is zero downside to filing. The only risk is not filing.
※ All information is based on 2026 statutory rates and official publications. Individual circumstances may vary. This is not professional financial, medical, or legal advice.