A tax bracket is one slice of taxable income with its own rate. Income tax is worked out slice by slice: the first slice at the lowest rate, the next at the next, and so on, so each rate applies only to the income that falls inside its own bracket, as the IRS puts it. In Britain the same slices are called bands.
Take a single American filer with $58,900 of taxable income in 2026. The first $12,400 is taxed at 10%, which is $1,240. The next $38,000, up to $50,400, is taxed at 12%, which is $4,560. The last $8,500 is in the 22% bracket and costs $1,870. The total is $7,670, about 13% of taxable income, even though the top bracket reached is 22%. The thresholds come from the IRS 2026 adjustments, which move them with inflation each year.
That arithmetic is why a pay rise cannot leave you worse off through income tax alone. Crossing into a higher bracket changes the rate on the pounds or dollars above the line and nothing below it. The bracket you are in sets your marginal tax rate; your overall rate is lower.
UK bands run on income after the personal allowance: 20% on the first £37,700 of taxable income, 40% up to £125,140 and 45% above, with Scotland setting six bands of its own, according to GOV.UK. Withdrawing the allowance above £100,000 creates a hidden 60% rate that no table of bands shows.
The take-home pay calculator shows a by band table under each income tax line, listing how much of your income sits in each bracket and what it costs.