How it works
- South Korea: total wage minus the monthly non-taxable allowance, minus the earned-income deduction, per-person deductions and annual social insurance gives the tax base. Progressive rates, the earned-income tax credit and 10% local tax follow. Dependents count only if they are 20 or younger, 60 or older or have a disability; each dependent aged 70+ adds ₩1,000,000 and each with a disability ₩2,000,000, and the 60+ worker pays no national pension.
- United States: gross minus the standard deduction gives federal taxable income. Social Security (6.2% up to $184,500) and Medicare (1.45%) are added, plus state tax for California, New York, Texas, Florida and Washington. Filers aged 65 or older add an extra standard deduction and the 2025–2028 senior deduction.
- United Kingdom: gross minus the personal allowance (£12,570, tapered above £100,000) is taxed in bands — 20/40/45% in England, Wales and Northern Ireland, six bands from 19% to 48% in Scotland — plus National Insurance.
Good to know
- Korean card, medical and education deductions differ by person and settle at year-end filing.
- US state tax is estimated for single and joint filers. New York City and other local taxes are excluded.
- UK pension contributions and student-loan repayments are excluded from the estimate.
- All figures use 2026 statutory tables and are reference estimates, not tax advice.
Standards and sources
- National Tax Service (Korea) — income tax rates
- National Tax Service (Korea) — withholding table
- National Pension Service (Korea) — contribution rates
- National Health Insurance Service (Korea) — premium rates
- IRS — federal income tax rates and brackets
- IRS — 2026 inflation adjustments (Rev. Proc. 2025-32)
- Social Security Administration — FICA rates and wage base
- California Franchise Tax Board — state income tax
- NY State Department of Taxation and Finance — state income tax
- GOV.UK — Income Tax rates and allowances
- GOV.UK — Scottish Income Tax
- GOV.UK — National Insurance
Last reviewed October 8, 2026
Frequently asked questions
How accurate is the Korean estimate?
It annualizes your pay: total wage minus the non-taxable allowance, minus the earned-income deduction, per-person deductions and annual social insurance gives the tax base. Progressive rates, the earned-income tax credit and 10% local tax follow. Card, medical and education deductions differ by person and settle at year-end, so treat the result as an estimate. Dependents qualify for the basic deduction only if they are 20 or younger, 60 or older, or have a disability. Each dependent aged 70 or older adds ₩1,000,000, each dependent with a disability adds ₩2,000,000, and workers aged 60 or older pay no national pension.
Which US taxes are included?
Federal income tax with the standard deduction, Social Security (6.2% up to $184,500) and Medicare (1.45%), plus state tax for California, New York, Texas, Florida and Washington. New York City and other local taxes are excluded, and state tax is estimated for single and joint filers. Filers aged 65 or older add $2,050 (single) or $1,650 per spouse (joint) to the standard deduction and can claim the 2025–2028 senior deduction of up to $6,000 each, phased out above $75,000 single / $150,000 joint.
How does the UK calculation work?
England, Wales and Northern Ireland use 20/40/45% bands with a £12,570 personal allowance that tapers above £100,000. Scotland uses six bands from 19% to 48%. National Insurance (8%/2%) is added in both cases, while pension and student-loan repayments are excluded.
Is the result guaranteed?
No. It is a reference estimate from 2026 statutory tables. Actual withholding follows company payroll rules and the final bill settles at year-end filing.