Why kr-utils?
kr-utils is a small set of free, sign-up-free tools for the awkward calculations every foreigner in Korea hits sooner or later — when does my visa expire, how much customs duty will I owe on that Amazon package, what's my T-money fare to Incheon Airport, how do I write my Korean address in English on a UK bank form, is the 19% flat tax really cheaper than progressive? 25 tools, all Korea-specific, all in your browser.
Built for expats on D-2, D-4, D-10, E-1 through E-7, F-2, F-4, F-5, F-6 visas, exchange students, digital nomads on K-ETA, business travelers, and Korean families with foreign-resident relatives. Each tool reflects the actual rule (NTS bracket tables, Immigration Service fee schedules, KORAIL and Seoul Metro fare matrices) rather than rounded ballparks.
No account, no install — your inputs stay on your device, never sent to our server. Site analytics (GA4) and ads (AdSense) load only after the page paints. Inputs stay on your device. Calculations are updated when Korean law or rates change — VAT 10%, four-insurance January refresh, ARC fee changes, holiday calendar revisions. Every tool's H1 shows the calibration date so you know what year's rules applied.
📖 In-depth Guides for Foreigners
Complete walkthroughs for life in Korea — written for D / E / F visa holders, long-term residents, and overseas Koreans. Each guide pairs with relevant calculators above.
Who is this for?
Long-term expats (D / E / F visas)
Working professionals, intra-company transferees, F-2 / F-5 / F-6 holders. Track ARC expiry, compare flat 19% vs progressive tax, calculate take-home with NPS opt-out option. Start with Visa Tracker or Foreigner Tax.
International students (D-2 / D-4)
University and language-school students. Need ARC renewal checklist before semester ends, T-money subway fare for Seoul commute, Korean address in English for home-country bank. Start with ARC Renewal or Subway Fare.
Travelers and short-term visitors
Tourists, K-ETA arrivals, business travelers. Public holidays calendar so you don't book during Seollal closures, customs duty estimator for online orders shipped to your hotel, etiquette quiz before your first hoesik dinner. Start with Korean Holidays or Customs Calculator.
Foreign business owners and freelancers
Self-employed, sole proprietors, foreign-corporation Korean branches. Korean VAT 10% supply ↔ gross conversions, simplified-tax-payer rates, BRN (10-digit) and Corporate Number (13-digit) checksum validators when vetting Korean partners, expat salary calculation for hiring locally. Start with VAT Calculator, BRN Validator, or Corporate Number Validator.
Multinational families and K-pop / K-drama fans
Mixed-nationality households (F-6 marriage), overseas Koreans (F-4), curious learners sending letters home. Korean age vs international age (the 2023 law confused everyone), name-to-passport romanization for kids, Korean BMI thresholds (23/25, not WHO 25/30), date math (1000 days from today, days between two events). Start with Korean Age, Name Romanizer, or Date Calculator.
Cross-border shoppers and shippers
Anyone shipping to or from Korea — Amazon Japan haul, US-to-Korea relocation, eBay sellers. Customs duty + 10% VAT estimator (haeoejikgu rules), Korean address romanizer for return forms, T-money for the airport bus. Start with Customs or Address Converter.
Frequently asked
Are these tools free?
Yes — every tool on kr-utils is 100% free. No subscription, no premium tier, no paywall on results, sharing, or export. The site is funded by non-intrusive footer ads that never block calculation results. There is no in-app purchase or trial expiration.
Do I need to sign up or create an account?
No signup, no login, no email verification, no app install. Open the page and start using the tool. Your inputs stay on your own device (browser localStorage) — nothing is sent to a server. A few tools (visa tracker, ARC renewal checklist) save inputs locally so you can come back to them, but the data never leaves your phone or laptop.
Are calculations updated for current Korean laws and rates?
Yes. Tax rates (foreigner flat 19%, progressive 6–45%, VAT 10%) follow National Tax Service (NTS) updates, the four-insurance rates refresh every January, and visa fees / ARC procedures track HiKorea and Immigration Service announcements. Each tool's H1 shows a date stamp (e.g. "2026.05 basis") so you know which year the result is calibrated for.
Can I use these tools on my phone?
Mobile-first by design. Works in iPhone Safari, Android Chrome, Samsung Internet, and any in-app browser. Add to Home Screen to install as a PWA — runs full-screen like a native app, offline-capable for most calculators. Optimized for one-handed use on the subway, in line at immigration, or at the customs desk.
Where do I find the Korean version?
If you read Korean (or are sending the link to a Korean colleague, spouse, or HR contact), the Korean-language sister site utilkit lives at krutils.com/utilkit/. It has 44 tools focused on domestic Korean life — annual leave under Labor Standards Act §60, take-home pay with four-insurance, jeonse-to-monthly conversion, freelancer 3.3% tax, comprehensive income tax (May filing), stock tax (capital gains + dividends), and more.
Who maintains kr-utils and how accurate are the results?
kr-utils is independently maintained as a side project — not affiliated with the Korean government, NTS, or any visa agent. Calculations are derived from official sources (NTS, hikorea.go.kr, Korea Tourism Organization, MOLIT) and unit-tested against published examples. Results are estimates for planning; for final tax filings, visa applications, or large financial decisions, confirm with a licensed tax accountant, immigration lawyer, or the relevant agency.