Tinker Tools

Free Online Calculators

Financial planning, health metrics, and tax estimation — all in one place. Pick a calculator to get instant, transparent results.

Salary After Tax

Calculate your net salary after South Korean income tax and social insurance deductions.

Monthly Salary Calculator

Calculate monthly take-home pay with South Korean tax brackets and insurance premiums.

Severance Pay Calculator

Calculate severance pay based on Korean labor law. Enter work period and average wage.

Pension Calculator

Simulate DB and DC pension plans for Korean retirement planning. Compare returns.

Tax Refund Calculator

Estimate your year-end tax refund in South Korea based on deductions and credits.

Mortgage Calculator

Calculate monthly mortgage payments with principal and interest amortization schedule.

Loan Interest Calculator

Calculate simple and compound interest on loans. Compare different repayment schedules.

Credit Card Interest Calculator

Calculate installment and revolving credit card interest to manage your finances better.

Currency Converter

Convert between world currencies with live exchange rates from a free public API.

Inflation Calculator

Calculate the impact of inflation on purchasing power over time with adjustable rates.

BMI Calculator

Calculate your Body Mass Index with height and weight. See your BMI category and health range.

Calorie Calculator

Calculate daily calorie needs using the Mifflin-St Jeor equation based on your activity level.

Health Insurance Calculator

Calculate Korean national health insurance premiums based on your income and employment type.

Health Insurance Voluntary

Compare voluntary continuation vs regional health insurance premiums after leaving employment in Korea.

Crypto Tax Calculator

Calculate capital gains tax on cryptocurrency transactions in Korea with 2.5M KRW exemption.

Inheritance & Gift Tax

Estimate Korean inheritance and gift tax with progressive rates (10–50%) and relationship-based deductions.

Unemployment Benefit Calculator

Estimate Korean unemployment benefit amount and duration based on your age, tenure, and average wage.

Freelancer Tax (3.3%)

Calculate net income for Korean freelancers after 3.3% withholding tax and estimated income tax.

Military Discharge Date

Calculate your military discharge date based on enlistment date and branch of service in Korea.

About These Calculators

Financial decisions are hard to make without numbers. How much of your salary actually reaches your bank account after taxes and insurance? How much interest will you pay over a 30-year mortgage? What happens to your purchasing power after a decade of 3% inflation? These calculators turn vague questions into concrete answers.

The Korean tax calculators form the core of this collection. The Salary After Tax calculator applies current income tax brackets, national pension, health insurance, employment insurance, and long-term care insurance to show your net pay. The Monthly Salary Calculator breaks that down on a monthly basis. For year-end settlement, the Tax Refund Calculator estimates whether you owe additional tax or can expect a refund based on your deductions and credits. And the Severance Pay Calculator computes your entitlement under Korean labor law when leaving a job.

Loan and debt calculators help you plan larger purchases. The Mortgage Calculator generates a full amortization schedule showing how much of each payment goes toward principal versus interest. The Loan Interest Calculator compares simple and compound interest across different repayment terms, and the Credit Card Interest Calculator shows the true cost of installment and revolving credit — numbers your credit card statement does not make obvious.

For retirement planning, the Pension Calculator simulates both DB (defined benefit) and DC (defined contribution) plans, so you can compare expected returns and plan accordingly. The Currency Converter pulls live exchange rates, and the Inflation Calculator shows how prices change over time — useful for long-term financial modeling.

Health calculators round out the set. The BMI Calculator classifies your body mass index, the Calorie Calculator estimates daily energy needs using the Mifflin-St Jeor equation, and the Health Insurance Calculator computes Korean national health insurance premiums.

Newer additions expand the collection further. The Crypto Tax Calculator computes capital gains tax on cryptocurrency transactions with the 2.5 million KRW basic deduction. The Inheritance & Gift Tax Calculator applies Korea's progressive 10–50% rates with relationship-based deductions. The Unemployment Benefit Calculator estimates your benefit amount and duration, and the Freelancer Tax Calculator shows your net income after the 3.3% withholding. The Health Insurance Voluntary Calculator compares voluntary continuation vs regional premiums, and the Military Discharge Date Calculator counts down to your discharge date. Every calculator shows its formula and assumptions — no black boxes, just transparent math.

Frequently Asked Questions

How accurate are the Korean tax calculators?
The tax calculators use official 2026 brackets and social insurance rates published by the National Tax Service and related agencies. They are designed for estimation — for official filings, consult a licensed tax accountant.
Where does the Currency Converter get exchange rates?
It pulls live rates from a free public API that aggregates data from central banks and financial institutions. Rates are refreshed regularly, though they may differ slightly from your bank's retail rate.
Can I use the Mortgage Calculator for non-Korean mortgages?
Yes. The mortgage math (principal, interest, amortization) is universal. Enter your loan amount, interest rate, and term in any currency. The calculator produces monthly payment schedules that work regardless of country.
What formula does the BMI Calculator use?
It uses the standard BMI formula: weight in kilograms divided by height in meters squared. The tool accepts both metric and imperial inputs and shows your BMI category (underweight, normal, overweight, obese) based on WHO classifications.
Is the Calorie Calculator reliable for diet planning?
It uses the Mifflin-St Jeor equation, which is widely regarded as one of the most accurate resting metabolic rate formulas. Results are estimates — individual metabolism varies. Use the output as a starting point and adjust based on real-world results.
Do these calculators store my financial data?
No. All calculations happen in your browser. Your salary, tax details, loan amounts, and health data are never sent to a server or stored anywhere. Close the tab and the data is gone.