Salary Comparison Calculator

Adjusting the salary slider updates the comparison chart in real time, showing monthly net pay, four-insurance deductions, and income tax across salary tiers. The raise simulation table lets you compare salary, net pay growth, and net pay ratio by raise rate, helping you understand which tier your salary falls into.

Korean income tax uses a progressive rate structure. As salary rises, higher tax brackets apply, so the net pay increase percentage is lower than the gross increase — your after-tax raise is always smaller than your gross raise.

The calculator applies the statutory employee contribution rates — health insurance, long-term care insurance, national pension, and employment insurance — based on monthly pay. Changing the salary slider or the number of dependents updates the insurance deduction items in the comparison chart in real time. Employer contributions are not included; only the amounts actually deducted from the employee's paycheck are shown.

Income tax uses a progressive rate structure, so as salary rises, higher tax brackets apply. A portion of the gross raise is absorbed by the increased tax burden, meaning the actual take-home increase is smaller than the gross increase. The same raise amount produces a smaller after-tax take-home increase at higher salary levels. You can see this gap directly in the net take-home rate column of the Salary Comparison Calculator.

The distinction between effective tax rate (total tax ÷ full taxable income) and marginal tax rate (the rate applied to each additional won of income) explains this clearly. A raise sits on top of existing income, so it faces the marginal rate — but the income below remains taxed at lower bracket rates, keeping the effective rate below the marginal rate. For salary negotiations, the marginal rate is the key figure that determines how much of a raise reaches your take-home, especially around bracket boundaries.

The net pay rate is monthly take-home divided by monthly gross pay — it shows what share of your gross salary you actually receive after taxes and four major insurance deductions. As salary rises, the progressive tax effect lowers the net pay rate, which you can see in the raise simulation table. The per-bracket net pay rate column makes it easy to spot at a glance where the deduction burden increases most sharply.

By checking the net pay rate and after-tax amount for each salary level in the raise simulation table, you can find the point just before and after a bracket boundary where the net pay rate noticeably drops. Moving the slider in small increments near income tax bracket thresholds lets you directly catch the moment deductions change. Use this to confirm in advance which bracket your salary negotiation target falls into.