Core answer: a trustworthy take-home-pay calculator passes four checks: city-specific social-insurance rates, all seven special additional deductions, cumulative-withholding individual income tax, and a full breakdown of the result. Sanity test: ¥20,000/month in Beijing with no deductions nets about ¥14,660.

The four checks

CheckPassCommon flaw
Social insurancecity presets + customone national rate
Special deductionsall 7 selectableonly the ¥5,000 threshold
Tax algorithm7 brackets + quick deductionsingle-rate estimate
Breakdowninsurance/fund/tax/net listedone bare number

Working out ¥20k in Beijing

Beijing employee rates: pension 8% + medical 2% + unemployment 0.5% + housing fund 12% = 22.5%, i.e. ¥4,500. Taxable = 20,000 − 4,500 − 5,000 = ¥10,500, in the 10% bracket with a 210 quick deduction — about ¥840/month on average (lower early in the year under cumulative withholding). Take-home ≈ 20,000 − 4,500 − 840 = ¥14,660; roughly ¥176k per year.

Monthly (Beijing, no deductions)Insurance + fundAvg taxTake-home
¥10k2,250~83~7,667
¥15k3,375~365~11,260
¥20k4,500~840~14,660
¥30k6,750~2,090~21,160

What moves your take-home

  • City: fund rates 5-12%; the same salary nets differently by hundreds across cities
  • Contribution base: actual salary vs minimum base can differ by a thousand a month
  • Special deductions: child education ¥2,000/child, mortgage interest ¥1,000, elderly care up to ¥3,000
  • Bonus taxation: separate vs merged annual bonus can differ by thousands

Example: the real gain from a 30% raise

¥15k → ¥20k in Beijing: nominal +¥5,000 (+33%), but take-home rises from ¥11,260 to ¥14,660 — only +¥3,400 (+30%), because the marginal bracket jumps from 3% to 10%. Negotiate in after-tax terms; if the new offer is in another city, fold in its insurance rates and bases too.

Example: three deductions, ¥7.7k/year saved

¥20k/month in Beijing with one child (¥2,000), a first-home mortgage (¥1,000) and elderly care as an only child (¥3,000): ¥6,000/month of deductions. Taxable drops from 10,500 to 4,500, monthly tax from ~¥840 to ~¥200 — about ¥640 more per month, ¥7,700 per year. Many never file these and voluntarily overpay.

Common mistakes

  • "Net = gross − tax": social insurance (up to 22.5%) is the bigger bite — deduct it before tax.
  • "Tax should be flat across months": cumulative withholding makes later months jump brackets — a shrinking paycheck is not a payroll error.
  • "Housing fund is a loss": it is fully yours, and the employer matches it — a 12% contribution is effectively a 12% raise.
  • "Deductions apply automatically": they must be filed in the tax app and updated after job changes or a new child.