Examples¶

Worked take-home calculations across the 2025/26 UK tax bands, including the £100,000 allowance taper edge cases. All figures are annual, in GBP (£), and computed with this crate.

Basic-rate salary¶

A £40,000 salary sits entirely inside the 20% band. Personal Allowance is untouched (well below the £100k taper), so taxable income is £27,430.

use uk_paye::{income_tax, national_insurance, take_home};

let gross = 40_000.0;

// Income tax: 20% of (40,000 - 12,570) = £5,486.00
assert!((income_tax(gross) - 5_486.00).abs() < 1e-6);

// NI: 8% of (40,000 - 12,570) = £2,194.40
assert!((national_insurance(gross) - 2_194.40).abs() < 1e-6);

let (net, tax, ni) = take_home(gross);
// net = 40,000 - 5,486.00 - 2,194.40 = £32,319.60

	£
Gross	40,000.00
Income tax	5,486.00
National Insurance	2,194.40
Take-home	32,319.60

At the higher-rate boundary¶

£50,000 is below the £50,270 higher-rate line, so income tax is still all 20%. NI is also still entirely in the 8% main band.

use uk_paye::take_home;

let (net, tax, ni) = take_home(50_000.0);
// net ≈ 39,519.60   tax ≈ 7,486.00   ni ≈ 2,994.40

	£
Gross	50,000.00
Income tax	7,486.00
National Insurance	2,994.40
Take-home	39,519.60

Just above the UEL (40% + 2% NI)¶

At £60,000 income tax crosses into the 40% band, and employee NI drops to 2% on the slice above £50,270.

use uk_paye::{income_tax, national_insurance, take_home};

let gross = 60_000.0;

// Allowance still full (£12,570); taxable £47,430.
// 20% on £37,700 + 40% on £9,730 = 7,540.00 + 3,892.00 = £11,432.00
assert!((income_tax(gross) - 11_432.00).abs() < 1e-6);

// NI: 8% on (50,270 - 12,570) + 2% on (60,000 - 50,270)
assert!((national_insurance(gross) - 3_210.60).abs() < 1e-6);

let (net, _, _) = take_home(gross);
// net ≈ 60,000 - 11,432.00 - 3,210.60 = £45,357.40

The £100k taper (60% marginal rate)¶

This is the case a naive calculator gets wrong. Between £100,000 and £125,140 the Personal Allowance is withdrawn at £1 per £2 earned. Each £2 of extra salary is taxed at 40% and drags £1 of income from 0% into the 40% band — a 60% effective marginal rate on income tax alone.

use uk_paye::personal_allowance;

// £100,000: full allowance, taper just starting.
assert!((personal_allowance(100_000.0) - 12_570.0).abs() < 1e-6);

// £110,000: allowance reduced by (110,000 - 100,000) / 2 = £5,000 -> £7,570.
assert!((personal_allowance(110_000.0) - 7_570.0).abs() < 1e-6);

// £125,140: allowance tapered to exactly zero.
assert!(personal_allowance(125_140.0).abs() < 1e-6);

A useful way to see the trap: compare the marginal cost of earning an extra £1,000 just below versus just inside the taper.

use uk_paye::take_home;

let before = take_home(99_000.0).0;
let after  = take_home(100_000.0).0;
// Just below the taper: ~£580 net of an extra £1,000 gross.

let before = take_home(110_000.0).0;
let after  = take_home(111_000.0).0;
// Inside the taper: only ~£400 net of an extra £1,000 gross
// (60% effective income-tax rate + 2% NI).

Additional rate¶

Above £125,140 the allowance is already zero and the 45% additional rate applies to everything above that line. The taper is over, so marginal rates drop back to a flat 45% + 2% NI.

use uk_paye::{income_tax, take_home};

// £150,000: £0 allowance.
// 20% of 37,700 + 40% of 74,870 + 45% of 24,860 = £54,331.50
assert!((income_tax(150_000.0) - 54_331.50).abs() < 1e-6);

let (net, _, _) = take_home(150_000.0);
// net ≈ 150,000 - 54,331.50 - 5,010.60 = £90,657.90

Gross	Personal Allowance	Income tax	NI	Take-home
12,570	12,570.00	0.00	0.00	12,570.00
30,000	12,570.00	3,486.00	1,394.40	25,119.60
40,000	12,570.00	5,486.00	2,194.40	32,319.60
50,000	12,570.00	7,486.00	2,994.40	39,519.60
60,000	12,570.00	11,432.00	3,210.60	45,357.40
80,000	12,570.00	19,432.00	3,610.60	56,957.40
100,000	12,570.00	27,432.00	4,010.60	68,557.40
110,000	7,570.00	33,432.00	4,210.60	72,357.40
125,140	0.00	43,144.50	4,513.40	77,482.10
150,000	0.00	54,331.50	5,010.60	90,657.90
200,000	0.00	76,831.50	6,010.60	117,157.90

Note the jump between £100,000 and £110,000: taxable income rises by £16,000 (the £10,000 raise plus the £5,000–£6,000 of lost allowance across the band), which is the taper at work.

Loop over a salary scale¶

A common need is take-home across a salary ladder — e.g. for a pay-rise visualisation.

use uk_paye::take_home;

let scale: Vec<f64> = (0..=10).map(|i| (i as f64) * 20_000.0).collect();
for gross in scale {
    let (net, tax, ni) = take_home(gross);
    println!("{gross:>9.0}  net {net:>10.2}  tax {tax:>9.2}  ni {ni:>8.2}");
}

These are the same figures the UKMoneyCalc take-home calculator renders interactively.