Korean Freelancer Tax Refund — Last 5 Days Before the June 1, 2026 Deadline

If you're a freelancer, indie hacker, or solo founder in Korea, the Jongso (종합소득세 / Comprehensive Income Tax) filing window closes on June 1, 2026 (Monday).

The statutory deadline is May 31, but because May 31 falls on Sunday this year, the National Tax Service (NTS / 국세청) extended the cutoff by one weekday. (nts.go.kr official, tossbank explainer)

This post is the same 5-day checklist I shipped on saemoey.vercel.app — a Korean tax-and-grant assistant I built as a solo founder. If you'd rather skim it in Korean, the original lives here: saemoey D-day post.

Why this matters for solo founders

In Korea, payment platforms withhold 3.3% from freelancer invoices at source (3% income + 0.3% local income tax). For most one-person businesses, the withheld amount overshoots the actual tax owed — meaning the May filing is usually a refund event, not a payment event.

Refunds typically land between late June and early July, per the NTS schedule. If you skip the filing, you forfeit the refund AND start accumulating late-filing penalties on Day 1 past the deadline. (banksalad guide)

The D-5 checklist

Day 1 (today) — Gather

• Aggregate all 3.3% invoices issued to you in 2025 (each platform usually exposes a tax-statement export).
• Pull last year's 종합소득세 PDF from Hometax if you filed before — same fields apply.
• Make sure your business registration number (사업자등록번호) matches what platforms reported.

Day 2 — Expense receipts (3만원+ rule)

Korean tax code requires proper substantiation (tax invoice / credit card receipt / cash receipt) for any business expense over ₩30,000.

Common deductible categories for a one-person SaaS or content business:

• Server / hosting (Vercel, Hetzner, AWS — convert USD to KRW at year-average rate)
• SaaS subscriptions (Figma, Notion, GitHub Copilot, ChatGPT Plus)
• Coworking / virtual office (deductible for both freelancers and 1-person 사업자)
• Coffee meetings with explicit business purpose (keep the agenda)
• Phone and internet (proportional to business use)

If you don't have receipts, you can still claim the 표준경비 (standard expense rate) based on your business code — usually 20-30% of revenue for solo content / IT businesses.

Day 3 — Deductions and credits

The three knobs that actually move the bill:

1. 노란우산공제 (Noran Umbrella Mutual Aid) — up to ₩5,000,000/year deduction for small business owners. Higher-bracket earners benefit more.
2. 개인연금 / IRP — capped tax credit, but real money.
3. 건강보험 / 국민연금 — paid premiums are fully deductible.

Day 4 — Pick your filing path

Three realistic options, ranked by cost:

Source: bukksket comparison, economist.co.kr.

Heads up: if you use SSEM or Toss, revoke the tax-agent authorization in Hometax after the refund lands. Otherwise they retain access to your tax records.

Day 5 — File and verify

• Submit on Hometax. Don't wait for the 11:59 PM rush — server load gets ugly past 6 PM on the last day.
• Save the 접수번호 (receipt number). That's your only proof if anything goes sideways.
• Check Hometax → 환급금 조회 in early July for the refund.

What I built for this

saemoey.vercel.app is a free Korean-language guide hub with:

• 5 D-day-aware blog posts covering jongso / yeonmaljeongsan / VAT / freelancer 3.3% / saju-business tax
• An AI chatbot that answers tax questions in plain Korean
• A saju-business hub for the niche I came from (online consulting + saju content)

The PRO tier is ₩2,900/month for unlimited AI consults and ad removal — cheaper than a single SSEM commission on a ₩50k refund.

Mistakes I see solo founders make

1. Filing nothing because revenue is ₩0 — you still need to file 무실적 (zero-revenue) or NTS escalates next year.
2. Mixing 일반과세 / 간이과세 expense rules — they're different deduction stacks.
3. Forgetting the 50% regional discount for businesses outside Seoul/수도권 — confirmed for designated regions.
4. Letting SSEM keep tax-agent authorization — revoke it after the refund.

If you're not in Korea

The Korean tax-month is brutal in volume (every freelancer files in the same 31 days) but mechanically simple compared to the US Schedule C. The lesson that transfers: build the checklist before the deadline week, not during it.

If you ship in Korea and want the Korean original, here it is: saemoey.vercel.app/guide/posts/02. Filing path picker on the homepage.

5 days left. Don't leave the refund on the table.