Take-home pay is not set by the annual salary — how social insurance and the withholding table split the same ₩4M

Two employees earn ₩48M a year, ₩4M a month. One's account receives ₩3,395,748, the other's ₩3,560,880. Over ₩160,000 apart on the same salary. The difference was the number written in the dependents box. Take-home pay is not set by the salary. Social insurance comes out of pay by rate and income tax by the withholding table, and that table picks its cell by pay and family size. Most people receive their first paycheck without knowing what comes out of one twelfth of the salary or why. It is commonly memorized as some percentage of salary, but the ratio rises as pay rises.

Step ② The withholding table is where the ₩160,000 came from. Income tax is a table, not a rate. Pay bands run down the side and the number of dependents across the top, and the amount in that cell is withheld. Family size includes yourself, and children aged 8 to 20 cut it further. At ₩4M single, income tax of ₩195,960 and local income tax of ₩19,596 come out for take-home of ₩3,395,748; with a spouse and one child, income tax falls to ₩88,760 for ₩3,513,668, and with two children ₩3,560,880. Same pay, one family cell, ₩160,000. Dependents follow the year-end basic deduction: annual income ₩1M or less, children 20 or under, parents 60 or over, and a working spouse does not count. The table steepens as pay rises: 12.44% at ₩3M, 17.1% at ₩5M, 20.95% at ₩7M, so 'take-home is X% of salary' holds only in one band. Not knowing, you submit a blank dependents form, lose ₩160,000 a month, and lend it to the tax office until February.

Step ④ The year-end settlement is where provisional becomes final. Every month's income tax is provisional and is recomputed in February on the year's total pay. Over-withheld means a refund, under-withheld means a top-up, and even a wrong cell comes back in February. Only income tax returns; social insurance is a rate, and health insurance has its own April pay reconciliation. At ₩4M single, over ₩2.58M is withheld in a year, and card and insurance deductions bring part of it back. Someone at 80% may owe more in February; a big refund is not good and a top-up is not a loss, since the total is the same. The payslip check is four lines: ① gross − tax-free = taxable pay, ② taxable pay × rates = four insurance items, ③ taxable pay and family size → table income tax and 10% local income tax, ④ the dependents form and the withholding ratio election. With four matching lines, checking take-home is done; negotiating a salary in reverse is the next lecture.

All four steps are passed: social insurance by rate, income tax by table, tax-free items and the ratio, the February settlement. The same ₩4M split into ₩3,395,748 and ₩3,560,880 on the family cell. A blank form costs ₩160,000 a month, unseparated meals tens of thousands, missing documents the money that would come back. Two things to do now: check the tax-free and family-size boxes on the payslip, and choose 80/100/120 and submit it to the company. The table changes yearly and tax-free items vary by company, so check with payroll.