# kkuldogu Korea payroll & tax API

> 58 South Korea 2026 calculators for payroll, income tax, social insurance, labor-law entitlements, family benefits, property and inheritance, as JSON for AI agents. For reference only, not legal or tax advice. Uses official 2026 Korean rates and the same formulas as the kkuldogu.com calculators; actual payroll, NHIS/NPS notices and tax settlement can differ.

## Why use this instead of computing it yourself
- Korean rates change every January and July (minimum wage, pension and health insurance rates, the NTS withholding table, benefit caps). These are the 2026 values, last checked 2026-11-13; every response states its basisYear
- Results are tested, not estimated: tools with a kkuldogu.com calculator are compared against that calculator's on-screen result by automated tests (same rounding order); tools without one (taxes, loans, inheritance, housing points, court fees) are computed from statutes and standard formulas and checked against hand-worked cases
- Rounding follows Korean practice (10-won truncation on taxes and premiums, the simplified withholding table rather than a formula)

## How to call
- Free: MCP server (streamable HTTP, no auth) at https://api.kkuldogu.com/mcp — tool names use underscores, e.g. net_pay. Paid-only tools are listed there too but return payment instructions
- Paid REST: POST https://api.kkuldogu.com/v1/<tool> with a JSON body, paid per call in USDC via x402 on Base (eip155:8453). No account or API key; an unpaid request returns 402 with payment requirements
- Amounts are KRW numbers, dates are YYYY-MM-DD. Every response includes basisYear, disclaimer, input and result

## Docs
- [OpenAPI 3.1 spec](https://api.kkuldogu.com/openapi.json): every tool with input schema, price and example request/response
- [Tool list as JSON](https://api.kkuldogu.com/): input schemas, prices and examples
- [Tool pages](https://api.kkuldogu.com/tools/net-pay): one page per tool at https://api.kkuldogu.com/tools/<tool>

## Tools free over MCP (REST $0.01 per call)
- [net-pay](https://api.kkuldogu.com/v1/net-pay) ($0.01): South Korea take-home pay for an employee: monthly net salary after national pension, health and long-term care insurance, employment insurance, and withheld income tax (2026 NTS simplified withholding table) plus local income tax. Example body: {"annualSalary":50000000,"dependents":2,"children8to20":1}
- [social-insurance](https://api.kkuldogu.com/v1/social-insurance) ($0.01): South Korea four major social insurances (national pension, health, long-term care, employment) for a monthly wage: employee deductions and employer contributions at 2026 rates. Example body: {"monthlyPay":3500000}
- [severance-pay](https://api.kkuldogu.com/v1/severance-pay) ($0.01): South Korea statutory severance pay (toejikgeum): 30 days of average wage per year of service, with retirement income tax, from hire date, last working day and last 3 months of pay. Pass monthlyOrdinaryWage to apply the legal rule that the ordinary wage replaces a lower average wage (Labor Standards Act art. 2(2)); without it only the average wage is used. Rounding follows the Ministry of Employment and Labor severance calculator. Example body: {"startDate":"2021-03-02","lastWorkDate":"2026-10-31","monthlyPay":3500000}
- [retirement-income-tax](https://api.kkuldogu.com/v1/retirement-income-tax) ($0.01): South Korea retirement income tax on a severance payment: service-year deduction, converted-pay deduction, national and local tax, and the reduced tax if received as an IRP pension. Example body: {"severancePay":30000000,"startDate":"2018-03-02","lastWorkDate":"2026-10-31"}
- [annual-leave](https://api.kkuldogu.com/v1/annual-leave) ($0.01): South Korea paid annual leave under the Labor Standards Act: days currently available, remaining days, next accrual, and payout value of unused leave. Example body: {"startDate":"2023-03-02","referenceDate":"2026-10-31","usedDays":4,"monthlyOrdinaryWage":3000000}
- [unemployment-benefit](https://api.kkuldogu.com/v1/unemployment-benefit) ($0.01): South Korea unemployment benefit (job-seeking allowance, silup geupyeo): daily amount with 2026 cap and floor, number of benefit days, and total. Example body: {"lastWorkDate":"2026-10-31","age":35,"insuredYears":4,"monthlyPay":3200000}
- [parental-leave-benefit](https://api.kkuldogu.com/v1/parental-leave-benefit) ($0.01): South Korea parental leave benefit from employment insurance, month by month with caps, including the 6+6 both-parents scheme and single parents. Example body: {"monthlyOrdinaryWage":3500000,"months":12}
- [weekly-holiday-pay](https://api.kkuldogu.com/v1/weekly-holiday-pay) ($0.01): South Korea weekly holiday pay (juhyu sudang): the paid weekly rest allowance owed to workers contracted for 15+ hours a week, with weekly and monthly pay including it. Example body: {"hourlyWage":10320,"weeklyHours":20}
- [wage-conversion](https://api.kkuldogu.com/v1/wage-conversion) ($0.01): Convert between hourly wage, monthly salary and annual salary the South Korean way (monthly hours include paid weekly holiday hours, 209 for a 40-hour week), with a 2026 minimum wage check. Example body: {"amount":3000000,"unit":"monthly"}
- [minimum-wage-check](https://api.kkuldogu.com/v1/minimum-wage-check) ($0.01): Check a South Korean monthly wage against the 2026 minimum wage (KRW 10,320/hour): counts base pay, monthly regular bonus and cash welfare allowances, supports the 90% probation rate. Example body: {"monthlyBasePay":2000000,"monthlyWelfare":200000}
- [part-time-pay](https://api.kkuldogu.com/v1/part-time-pay) ($0.01): South Korea part-time (alba) monthly pay from an hourly wage and schedule, including weekly holiday pay, after either 3.3% withholding or the four social insurances plus income tax. Example body: {"hourlyWage":10320,"hoursPerDay":5,"daysPerWeek":5,"deduction":"freelancer_3_3"}
- [overtime-pay](https://api.kkuldogu.com/v1/overtime-pay) ($0.01): South Korea overtime, night and holiday work premiums under the Labor Standards Act (1.5x overtime, +0.5x night, 1.5x/2x holiday); workplaces with fewer than 5 employees get no premium. Example body: {"wage":12000,"overtimeHours":10,"nightHours":4,"holidayHours":8}
- [ordinary-wage](https://api.kkuldogu.com/v1/ordinary-wage) ($0.01): South Korea ordinary wage (tongsang imgeum): hourly and daily ordinary wage from base pay, fixed allowances and regular bonuses, the basis for overtime, unused leave and dismissal notice pay. Example body: {"monthlyBasePay":2800000,"monthlyFixedAllowances":300000}
- [average-wage](https://api.kkuldogu.com/v1/average-wage) ($0.01): South Korea average wage (pyeonggyun imgeum): daily average over the 3 months before the last working day, the basis for severance pay and unemployment benefit; falls back to the ordinary wage when that is higher. Example body: {"lastWorkDate":"2026-10-31","monthlyPay":3500000}
- [freelancer-withholding](https://api.kkuldogu.com/v1/freelancer-withholding) ($0.01): South Korea 3.3% business-income withholding for freelancers (3% income tax + 0.3% local tax), in either direction: net from gross, or the gross to invoice for a target net. Example body: {"amount":1000000}
- [daily-worker-tax](https://api.kkuldogu.com/v1/daily-worker-tax) ($0.01): South Korea daily (day-labor) worker tax: income tax after the KRW 150,000 daily deduction and 55% credit, local tax and employment insurance, for wages paid daily or in one lump sum. Example body: {"dailyWage":200000,"days":10}
- [other-income-tax](https://api.kkuldogu.com/v1/other-income-tax) ($0.01): South Korea other-income (gita sodeuk) withholding of 22% on income after deemed expenses, e.g. lecture fees, manuscript fees and prizes, with the KRW 50,000 exemption threshold. Example body: {"amount":500000}
- [dismissal-notice-pay](https://api.kkuldogu.com/v1/dismissal-notice-pay) ($0.01): South Korea dismissal notice allowance: 30 days of ordinary wage owed when an employer gives less than 30 days notice (not owed for under 3 months of service). Example body: {"noticeDate":"2026-11-10","dismissalDate":"2026-11-20","monthlyOrdinaryWage":3000000}
- [shutdown-allowance](https://api.kkuldogu.com/v1/shutdown-allowance) ($0.01): South Korea business shutdown allowance (hyueop sudang): 70% of average wage, or the ordinary wage if that is lower, for days the employer suspends work (5+ employee workplaces). Example body: {"monthlyAverageWage":3200000,"monthlyOrdinaryWage":2900000,"days":30}
- [maternity-leave-pay](https://api.kkuldogu.com/v1/maternity-leave-pay) ($0.01): South Korea maternity leave pay for 90 days (120 for multiple births): split between employer and employment insurance, with the 2026 monthly cap of KRW 2.2 million. Example body: {"monthlyOrdinaryWage":3500000}
- [paternity-leave-pay](https://api.kkuldogu.com/v1/paternity-leave-pay) ($0.01): South Korea spouse (paternity) childbirth leave pay for the 20 paid days, and how much employment insurance covers at priority-support companies. Example body: {"monthlyOrdinaryWage":4000000}
- [reduced-hours-childcare-benefit](https://api.kkuldogu.com/v1/reduced-hours-childcare-benefit) ($0.01): South Korea reduced working hours for childcare benefit: monthly employment-insurance top-up (first 10 reduced hours at 100%, rest at 80%, with caps) plus the reduced employer pay. Example body: {"monthlyOrdinaryWage":3500000,"weeklyHoursAfter":30,"months":12}
- [monthly-rent-tax-credit](https://api.kkuldogu.com/v1/monthly-rent-tax-credit) ($0.01): South Korea monthly rent (wolse) tax credit at year-end settlement: 17% or 15% of up to KRW 10 million rent for homeless tenants earning up to KRW 80 million. Example body: {"grossSalary":40000000,"monthlyRent":600000}
- [pension-savings-tax-credit](https://api.kkuldogu.com/v1/pension-savings-tax-credit) ($0.01): South Korea pension savings and IRP tax credit: 16.5% or 13.2% (incl. local tax) of contributions up to KRW 9 million, and the extra refund from filling the remaining limit. Example body: {"grossSalary":50000000,"pensionSavings":4000000}
- [vat](https://api.kkuldogu.com/v1/vat) ($0.01): South Korea 10% VAT: split a VAT-inclusive total into supply amount and VAT, or add VAT to a supply amount, with Korean rounding. Example body: {"amount":1100000,"mode":"total"}
- [brokerage-fee](https://api.kkuldogu.com/v1/brokerage-fee) ($0.01): South Korea real-estate brokerage fee ceiling (bokbi) for a sale, jeonse or monthly-rent lease of a house or officetel: statutory rate bracket, fee cap and VAT. Example body: {"transaction":"sale","price":500000000}
- [jeonse-wolse-conversion](https://api.kkuldogu.com/v1/jeonse-wolse-conversion) ($0.01): Convert between South Korean jeonse deposit and monthly rent (wolse) at a conversion rate, with the statutory 4.5% cap check on a landlord's asked rent. Example body: {"jeonseDeposit":300000000,"newDeposit":100000000}
- [child-benefits](https://api.kkuldogu.com/v1/child-benefits) ($0.01): South Korea government cash support for a newborn: first-meeting voucher, parent benefit for ages 0-1 and the monthly child allowance up to age 9, with a dated schedule. Example body: {"birthDate":"2026-11-10"}
- [business-days](https://api.kkuldogu.com/v1/business-days) ($0.01): South Korea business days: count working days between two dates, or find the date N business days later, skipping weekends and Korean public holidays (2025-2027 table incl. substitute holidays). Example body: {"startDate":"2026-11-10","endDate":"2026-12-31"}
- [deposit-interest](https://api.kkuldogu.com/v1/deposit-interest) ($0.01): South Korea bank deposit or installment-savings interest after tax: maturity amount with simple or monthly-compounded interest and the 15.4% interest withholding tax (or 9.5% preferential, or tax-free). Example body: {"kind":"savings","amount":500000,"months":12,"annualRatePct":4}
- [korean-age](https://api.kkuldogu.com/v1/korean-age) ($0.01): Korean age calculation: international age (the legal standard in South Korea since June 2023), year age, traditional counting age, zodiac animal, and the next birthday. Example body: {"birthDate":"1995-03-15","referenceDate":"2026-11-12"}
- [pyeong-conversion](https://api.kkuldogu.com/v1/pyeong-conversion) ($0.01): Convert between square meters and pyeong, the Korean real-estate area unit (1 pyeong = 400/121 m2, about 3.3058 m2). Example body: {"value":84}
- [pregnancy-due-date](https://api.kkuldogu.com/v1/pregnancy-due-date) ($0.01): Pregnancy due date and gestational week from the last menstrual period, with the South Korean labor-law dates that follow: reduced working hours in pregnancy, earliest maternity leave start, and the paternity leave deadline. Example body: {"lastPeriodDate":"2026-07-01","referenceDate":"2026-11-12"}
- [service-period](https://api.kkuldogu.com/v1/service-period) ($0.01): Length of service at a South Korean employer from the hire date: years, months, days, next anniversary, annual leave entitlement for the current year of service, and severance pay eligibility. Example body: {"startDate":"2022-03-02","referenceDate":"2026-11-12"}
- [income-tax-from-tax-base](https://api.kkuldogu.com/v1/income-tax-from-tax-base) ($0.01): South Korea comprehensive income tax from a tax base (gwase pyojun): the 8-bracket 6-45% progressive table with deduction amounts, plus 10% local income tax, marginal and effective rates. Example body: {"taxBase":50000000}
- [early-repayment-fee](https://api.kkuldogu.com/v1/early-repayment-fee) ($0.01): South Korea early loan repayment fee (jungdo sanghwan susuryo): repaid amount x fee rate x remaining days / fee period (usually 3 years, after which the fee is waived). Example body: {"repayAmount":100000000,"feeRatePct":1.2,"elapsedDays":365}
- [stock-transaction-tax](https://api.kkuldogu.com/v1/stock-transaction-tax) ($0.01): South Korea securities transaction tax on selling listed shares (2026 rates): KOSPI 0.05% plus 0.15% rural special tax, KOSDAQ 0.20%, charged on the sale amount whether or not there is a gain. Example body: {"sellAmount":10000000,"market":"kospi"}
- [unemployment-eligibility](https://api.kkuldogu.com/v1/unemployment-eligibility) ($0.01): South Korea unemployment benefit eligibility check: at least 180 insured days in the 18 months before leaving, an involuntary (or justified) reason for leaving, and being able and actively seeking work. Use unemployment-benefit for the amount. Example body: {"insuredDaysLast18Months":240,"reason":"contract_expiry"}
- [weekly-hours-check](https://api.kkuldogu.com/v1/weekly-hours-check) ($0.01): South Korea 52-hour workweek check under the Labor Standards Act: 40 standard hours plus at most 12 overtime hours a week (35 plus 5 for workers under 18); workplaces with fewer than 5 employees are exempt for adults. Example body: {"weeklyHours":55}

## Paid-only tools (REST with x402)
- [gross-from-net](https://api.kkuldogu.com/v1/gross-from-net) ($0.05): Reverse South Korea take-home pay: the gross monthly and annual salary needed to reach a target monthly net pay after 2026 social insurance and withheld income tax. Example body: {"targetNetMonthly":3000000}
- [year-end-tax-settlement](https://api.kkuldogu.com/v1/year-end-tax-settlement) ($0.10): South Korea year-end tax settlement (yeonmal jeongsan) estimate for employees: refund or additional tax from gross salary, dependents, card spending and the main deductions and credits, choosing itemized vs standard credit. Example body: {"grossSalary":50000000,"creditCard":15000000,"debitCash":5000000,"insurancePremiums":1000000,"medical":500000}
- [card-income-deduction](https://api.kkuldogu.com/v1/card-income-deduction) ($0.05): South Korea credit card income deduction for year-end settlement: deduction from credit, debit/cash, traditional market/transit and culture spending above 25% of salary, with limits and estimated tax saved. Example body: {"grossSalary":50000000,"creditCard":15000000,"debitCash":5000000,"traditionalMarketTransit":800000,"cultureSports":300000}
- [bonus-tax](https://api.kkuldogu.com/v1/bonus-tax) ($0.05): South Korea tax withheld on a bonus or incentive payment: income tax by the simplified-table bonus method over the payment period, local tax and employment insurance, and the net bonus. Example body: {"bonus":5000000,"monthlySalary":3800000,"periodMonths":12}
- [gift-tax](https://api.kkuldogu.com/v1/gift-tax) ($0.10): South Korea gift tax (jeungyeose) on a gift received: relationship deduction (spouse 600M, parent to adult child 50M, to minor 20M, other relatives 10M), 10-year aggregation, marriage/childbirth deduction, 10-50% progressive rates, generation-skipping surcharge and the 3% on-time filing credit. Example body: {"amount":150000000,"donor":"lineal_ascendant"}
- [housing-acquisition-tax](https://api.kkuldogu.com/v1/housing-acquisition-tax) ($0.05): South Korea acquisition tax when buying a home: 1-3% by price (sliding rate between 600M and 900M), 8%/12% heavy rates for multiple homes and corporations, plus local education tax and rural special tax, and the first-home relief of up to 2M. Example body: {"price":750000000}
- [vehicle-tax](https://api.kkuldogu.com/v1/vehicle-tax) ($0.05): South Korea annual vehicle tax (jadongchase) for a private passenger car: per-cc rate by engine displacement, 30% local education tax, age reduction from the 3rd year (5% a year, up to 50%), flat amount for electric cars, and the 2026 annual-prepayment discount. Example body: {"displacementCc":1998,"vehicleAgeYears":5,"prepayMonth":1}
- [loan-repayment](https://api.kkuldogu.com/v1/loan-repayment) ($0.05): Loan repayment schedule summary as used by South Korean banks: equal monthly payment (wolligeum gyundeung), equal principal (wongeum gyundeung) or interest-only with bullet repayment; monthly payment, first and last installments, total interest. Example body: {"principal":300000000,"annualRatePct":4.2,"months":360}
- [inheritance-shares](https://api.kkuldogu.com/v1/inheritance-shares) ($0.10): South Korea statutory inheritance shares and forced-heirship reserve (yuryubun) under the Civil Code: heirs by rank (children, then parents, then siblings), the spouse 50% add-on, and reserved portions (1/2 of the share for children and spouse, 1/3 for parents, none for siblings). Representation (daeseup) and heirs beyond siblings are not modeled. Example body: {"spouse":true,"children":2,"estate":700000000}
- [housing-subscription-score](https://api.kkuldogu.com/v1/housing-subscription-score) ($0.05): South Korea housing subscription points (cheongyak gajeom, max 84) for private apartment sales: homeless period (max 32), dependents (max 35) and subscription account period (max 17). The spouse-account bonus is not included. Example body: {"homelessYears":10.5,"dependents":3,"accountYears":7.2}
- [litigation-stamp-fee](https://api.kkuldogu.com/v1/litigation-stamp-fee) ($0.05): South Korea civil lawsuit filing costs: court stamp fee (injidae) from the claim amount by bracket, 1.5x on appeal and 2x at the Supreme Court, 10% off for electronic filing, plus the prepaid service-of-process fee (songdallyo). Example body: {"claimAmount":50000000}
- [late-payment-interest](https://api.kkuldogu.com/v1/late-payment-interest) ($0.05): South Korea statutory late-payment interest (jiyeon sonhaegeum) on a money debt: 5% civil, 6% commercial, 12% under the litigation-promotion act after a complaint is served, or a contract rate, prorated by day. Example body: {"principal":10000000,"startDate":"2026-01-01","endDate":"2026-10-31","rate":"litigation"}
- [resignation-settlement](https://api.kkuldogu.com/v1/resignation-settlement) ($0.10): South Korea resignation settlement in one call: statutory severance pay, retirement income tax and local tax, net severance, unused annual-leave pay, and how much more you get by moving the last working day (one more day, week, month, or until the next annual-leave grant). Uses the ordinary wage when it is higher than the average wage. Optionally adds the unemployment benefit estimate for an involuntary separation. Example body: {"startDate":"2023-03-02","lastWorkDate":"2026-03-01","monthlyPay":3500000,"unusedLeaveDays":5}
- [job-offer-comparison](https://api.kkuldogu.com/v1/job-offer-comparison) ($0.05): Compare a South Korean job offer with the current job on what actually matters: annual take-home pay including bonus (after 2026 social insurance and withholding tax), monthly take-home, and real hourly net pay once commuting time is counted. Assumes KRW 200,000 monthly non-taxable pay and 1 dependent. Example body: {"current":{"annualSalary":42000000,"annualBonus":2000000,"commuteMinutesPerDay":60},"offer":{"annualSalary":46000000,"commuteMinutesPerDay":100}}
- [rental-income-separate-tax](https://api.kkuldogu.com/v1/rental-income-separate-tax) ($0.05): South Korea housing rental income tax under separate taxation (annual rent up to 20 million KRW): 14% on rent minus deemed expenses (50%, or 60% for registered rental housing) and the basic deduction (2M, or 4M registered, only if other income is 20M or less), plus local income tax. Deemed rent on deposits and registered-housing tax reductions are not modeled. Example body: {"annualRent":9600000}
- [financial-income-tax](https://api.kkuldogu.com/v1/financial-income-tax) ($0.05): South Korea comprehensive taxation of financial income (interest and dividends over 20 million KRW a year): compares the comprehensive method (first 20M at 14%, the excess added to other income at 6-45%) with the 14% separate method and takes the larger, then shows tax due beyond what was withheld. Dividend gross-up and the 2026 high-dividend separate-taxation option are not modeled. Example body: {"financialIncome":50000000,"otherTaxBase":50000000}
- [severance-batch](https://api.kkuldogu.com/v1/severance-batch) ($0.10): South Korea statutory severance pay for up to 100 employees in one call: per-employee gross severance, retirement income tax and net amount using the same calculation as severance-pay (Ministry of Employment and Labor rounding, optional ordinary-wage comparison), with company-wide totals. Example body: {"employees":[{"id":"kim","startDate":"2021-03-02","lastWorkDate":"2026-03-01","monthlyPay":3500000},{"id":"lee","startDate":"2019-07-01","lastWorkDate":"2026-10-31","monthlyPay":4200000,"annualBonus":6000000}]}
- [payroll-batch](https://api.kkuldogu.com/v1/payroll-batch) ($0.10): South Korea monthly payroll run for up to 100 employees in one call: per-employee take-home pay with each deduction (national pension, health, long-term care, employment insurance, income tax from the 2026 NTS withholding table, local income tax), employer social-insurance contributions, and company-wide totals including total employer cost. Industrial accident insurance (industry-specific rate) is not included. Example body: {"employees":[{"id":"kim","annualSalary":40000000},{"id":"lee","monthlySalary":5000000,"dependents":3,"children8to20":1}]}
- [new-parent-benefits](https://api.kkuldogu.com/v1/new-parent-benefits) ($0.10): Everything a South Korean household receives around a birth, in one call: maternity leave pay (90/120 days, who pays what), parental leave benefit month by month (normal, 6+6 both-parents, or single-parent scheme), the spouse's 20-day childbirth leave pay, and government cash support for the child (first-meeting voucher, parent benefit, child allowance to age 9). Example body: {"birthDate":"2026-11-13","monthlyOrdinaryWage":3500000,"spouseMonthlyOrdinaryWage":4000000}