How income tax works.

Income tax is charged in slices. Nobody pays 40% on their whole salary, each band’s rate applies only to the income that falls inside that band. Three ideas explain almost everything on your payslip: the personal allowance, the bands, and the taper.

The personal allowance

The first £12,570 you earn in a tax year is tax-free with the standard tax code (1257L). Two things can enlarge it , Blind Person’s Allowance (£3,250 extra) and receiving Marriage Allowance from a partner (worth up to £252 off your bill), and one thing shrinks it: earning over £100,000.

The bands, England, Wales & Northern Ireland

Above the allowance, income is taxed at 20% up to £50,270 of total income, 40% from there to £125,140, and 45% beyond. On a £60,000 salary, only the £9,730 above £50,270 is taxed at 40%, the slice below it is still taxed at 20%.

Scotland’s six bands

Scotland sets its own rates on earned income: 19% (starter), 20% (basic), 21% (intermediate), 42% (higher, from £43,663 of total income), 45% (advanced, from £75,001) and 48% (top, above £125,140). Lower earners pay slightly less than in England; higher earners pay noticeably more. National Insurance and student loans stay UK-wide either way.

The £100,000 taper, the hidden 60% zone

Adjusted net income over £100,000 removes the personal allowance at £1 for every £2, until it is gone at £125,140. Losing allowance while gaining income means each £100 in that zone costs £60 in extra tax (£62 with National Insurance), a higher marginal rate than any official band. Pension contributions reduce adjusted net income, which is why they are so effective between £100k and £125k. See it live on the £110,000 breakdown.

What this site does with it

The calculator applies exactly these rules, allowance, taper, your country’s bands, then National Insurance and any student loan, and shows the working for every band, with the GOV.UK sources linked. Estimates, not tax advice.