UK Effective Tax Rate vs Marginal Tax Rate Explained 2025/26

Quick answer

For UK PAYE income in 2025/26:

• The effective tax rate is total tax (income tax + NI) divided by gross salary. It is always lower than the marginal rate because the first £12,570 is tax-free and the next £37,700 is taxed at only 20% / 8%.
• The marginal tax rate is the slice you lose on the next £1 you earn. It governs decisions about pension contributions, overtime, Gift Aid, salary sacrifice and bonus timing.

Confusing the two costs people money — typically by underestimating the real value of pension contributions, or by overestimating what a pay rise will deliver in cash.

The 2025/26 rUK marginal rate ladder

For England, Wales and Northern Ireland employees, the combined income tax + employee NI rate on the next £1 looks like this:

Self-employed Class 4 NI is 6% / 2% rather than 8% / 2%, so the equivalent ladder is 26% / 42% / ~62% / 47%.

Worked example 1 — £30,000 employee

Sara earns £30,000 in Manchester.

• Personal Allowance: £12,570 → £0 tax.
• Basic rate: £17,430 × 20% = £3,486 income tax.
• Employee NI: £17,430 × 8% = £1,394.
• Total deductions: £4,880.
• Take-home: £25,120.
• Effective rate: £4,880 / £30,000 = 16.3%.
• Marginal rate on the next £1: 28%.

If Sara is offered a £2,000 pay rise:

• Effective rate would barely move (to ~17%).
• But the rise is taxed entirely at 28% → she keeps £1,440, not £2,000.
• A 6.7% gross rise translates to a 5.7% net rise.

Worked example 2 — £55,000 employee

James earns £55,000 in Birmingham.

• Personal Allowance: £12,570 → £0 tax.
• Basic rate: £37,700 × 20% = £7,540.
• Higher rate: £4,730 × 40% = £1,892.
• Income tax: £9,432.
• NI: £37,700 × 8% + £4,730 × 2% = £3,016 + £95 = £3,111.
• Total deductions: £12,543.
• Take-home: £42,457.
• Effective rate: 22.8%.
• Marginal rate: 42%.

If James gets a £5,000 bonus:

• He keeps only £5,000 × (1 – 0.42) = £2,900.
• But if he salary-sacrifices the bonus into his workplace pension, he avoids the full 42% — and his employer often passes on their 15% NI saving too, adding ~£750 to his pension.

For most higher-rate earners, this is the key insight: the effective rate (22.8%) makes the salary look reasonable, but the marginal rate (42%) makes pension contributions extraordinarily efficient.

Worked example 3 — £105,000 in the 60% trap

Priya earns £105,000 in London.

• PA reduced: £100,000 + 2 × £12,570 = £125,140 zero-out point. At £105,000 the PA is reduced by (£5,000 / 2) = £2,500, leaving £10,070 of PA.
• This means the effective taxable income is £105,000 – £10,070 = £94,930.
• Income tax: £7,540 (basic) + £17,892 (higher 40% on £44,730) = roughly £25,432.
• NI: £3,016 + £1,295 = £4,311.
• Total deductions: ~£29,743.
• Take-home: ~£75,257.
• Effective rate: 28.3%.
• Marginal rate on the next £1: ~62%.

A £5,000 raise from £105k → £110k delivers only £1,900 of additional take-home. The same £5,000 sacrificed into pension keeps the full £5,000 in the pot at a real cost of just £1,900 — a 62% discount.

See the £100k tax trap post for the full mechanics of why the PA taper produces a marginal rate higher than the additional rate.

Worked example 4 — £130,000 (above the trap)

Tom earns £130,000.

• PA fully tapered away.
• Income tax: £7,540 + £19,892 + (£4,860 × 45%) = £7,540 + £19,892 + £2,187 = £29,619.
• NI: £3,016 + £1,594 = £4,610.
• Take-home: ~£95,771.
• Effective rate: 26.3%.
• Marginal rate: 47%.

Counterintuitively, Tom's marginal rate (47%) is lower than Priya's (62%). The 60% trap is a spike — once you push past £125,140 things ease slightly.

Why marginal rate is what matters for big decisions

Any "is it worth it?" question uses the marginal rate, not the effective rate:

1. Pension contributions: a higher-rate taxpayer sacrificing £1,000 only "spends" £580 of take-home (42% marginal), but adds £1,000 to the pension pot.
2. Gift Aid: a £100 donation grossed up to £125 reduces taxable income — the higher-rate top-up is worth 20% × £125 = £25 to the donor, plus PA restoration in the trap.
3. Bonus timing: pushing a bonus into a year where you avoid the £100k taper can swing tens of thousands.
4. Overtime: a basic-rate worker keeps 72p per overtime £1. A higher-rate worker keeps 58p. A £100k-trap earner keeps 38p.

For more on tactical use of the marginal rate, see reduce your income tax bill.

Why effective rate is what matters for comparisons

The effective rate is the honest description of your tax burden. Use it to:

• Compare net offers across jurisdictions (Scotland vs rUK).
• Describe affordability — your mortgage lender wants net pay, which depends on your effective rate.
• Plan budgets — the effective rate × gross is the realistic spendable income figure.

Scotland — different ladder, same idea

In Scotland in 2025/26 the income-tax marginal rates are:

A Scottish higher-rate earner at £55,000 has a marginal rate of 44% vs 42% in rUK — see our Scotland vs England income tax post for the full side-by-side.

Common misconceptions

"My bonus is taxed at 50%" — almost never true on the annual reconciliation. What people see is a one-month spike in cumulative PAYE, which evens out over the year unless the bonus genuinely pushes annual income into the 62% trap.

"I shouldn't earn over £100k or my whole salary gets taxed at 60%" — wrong. Only the slice between £100,000 and £125,140 is hit at ~62%. Existing salary below £100,000 keeps its previous rates.

"Higher effective rate means worse off" — usually true within a country, but Scotland's higher effective rates also fund free university tuition and slightly different prescription charges. Always compare net-of-everything position.

Using the calculators

Each one shows both your effective rate (top-line summary) and your marginal rate (next-pound deduction).

Sources

• HMRC: Income Tax rates and Personal Allowance
• HMRC: National Insurance rates
• Scottish Government: Scottish Income Tax 2025/26
• gov.uk: Income Tax Personal Allowance and basic-rate limit