Take-home pay is three subtractions
Step one: gross pay minus your share of social insurance and housing fund (pension 8%, medical 2%, unemployment around 0.5%, housing fund 5–12%, with local base caps and floors). Step two: subtract the monthly 5,000 allowance and any special additional deductions. Step three: apply the progressive rate table to what remains to get the month’s tax. That is why "what do I take home on 15,000 gross" needs the contribution base and fund rate first: small differences there move the answer by hundreds of yuan.
Why deductions grow later in the year
Tax is withheld cumulatively: each month uses the year-to-date taxable income times the applicable rate, minus tax already paid. Early in the year the cumulative amount sits in the lowest 3% band; as it crosses 36,000, 144,000 and further thresholds, the excess is taxed at higher rates, so the same salary shows a rising deduction from some month onwards. The employer did not miscalculate and your pay was not cut: the annual total is fixed, with any difference refunded or collected at the annual settlement. Bonuses and unpaid leave make the curve more visible.
What special deductions are worth
Six main categories: care for children under three, children’s education, continuing education, major medical expenses, mortgage interest or rent (only one of the two), and supporting elderly parents. They reduce taxable income directly, so the money saved equals the deduction times your marginal rate: at the 10% band each 1,000 yuan saves 100, at the 20% band it saves 200. Declare them truthfully through the official app — duplicate claims (for example both spouses deducting the same mortgage interest at 100%) are corrected at the annual settlement.
Bonuses: taxed separately or combined
The two methods can differ by thousands of yuan. Separate taxation divides the bonus by twelve to find a rate, then applies it to the full amount: useful because it does not stack on top of salary and usually lands in a lower band. Combining adds the bonus to annual income, which suits people whose total income is low and whose deductions are not fully used. Rule of thumb: if salary taxable income is in a low band and deductions remain unused, combining often wins; if salary already reaches higher bands, separate taxation usually costs less. The safe approach is to compute both and take the lower tax.
Where the contribution bases differ
Social insurance and housing fund have contribution bases with local caps and floors, normally set from last year’s average monthly wage, capped around three times the local average and floored at a minimum. Earning above the cap or below the floor breaks any "percentage of salary" estimate. The housing fund rate is chosen by the employer between 5% and 12%, matched by the employee: a higher rate lowers take-home pay, but the whole balance including the employer’s share is yours, so leave it out of total-pay comparisons at your peril. That is why identical gross pay yields very different take-home amounts across cities and employers.
Three common misunderstandings
First, "same salary means the same deduction": under cumulative withholding, different start dates or mid-year bonuses produce different curves. Second, "separate bonus taxation is always cheaper": for lower incomes it is often the opposite, so compute both. Third, "lower take-home means the payroll is wrong": check whether contribution bases were reset (commonly around July), whether a deduction lapsed, and whether you crossed a rate threshold. Review in that order — line items on the payslip, then recompute with the same inputs, then ask HR for the calculation — before assuming an error.
想马上动手：用 个税计算器 填税前工资、社保公积金基数与专项附加扣除，对比年终奖两种计税方式；金额需要写进合同或发票时，用 金额大写转换 核对；想算长期结余可以配合 复利计算。Try it now: enter your gross pay, contribution bases and special deductions in the income tax calculator and compare both bonus methods; for contracts and invoices, verify figures with amount in words, and plan long-term savings with compound interest.
FAQ
Can I use the result for filing my taxes?
No. Local contribution bases, rate rules and your personal deductions all affect the outcome, so this is for estimating and comparing. Use the official tax channels for filing.
Why is the monthly deduction different each month?
Because withholding is cumulative: once year-to-date taxable income crosses a rate threshold, the excess is taxed higher, so that month’s figure rises. The annual total is unchanged, with refunds or top-ups at settlement.
Which bonus method costs less?
It depends on annual income and unused deductions: combining often wins when salary sits in a low band with deductions to spare, while separate taxation usually costs less once salary reaches higher bands. Compute both.