What this calculator does
Takes both partners' incomes. Checks eligibility and calculates the annual tax saving from transferring part of the lower earner's personal allowance to the higher earner.
The formula
Transferable amount: up to £1,260 (10% of personal allowance, rounded up) (limited to the lower earner's unused allowance if less than £1,260) Eligibility: - Married or in a civil partnership - Lower earner's income ≤ £12,570 (within personal allowance) - Higher earner is a basic rate taxpayer (income ≤ £50,270) - Neither partner pays tax at the Scottish higher rate Annual saving = transfer amount × 20% Maximum saving = £1,260 × 20% = £252/year Can be backdated up to 4 tax years.
Assumptions
- The lower earner's income does not exceed the personal allowance (£12,570).
- The higher earner's income does not exceed the basic rate threshold (£50,270).
- Neither partner is subject to Scottish income tax at the higher rate.
Data sources
| Figure | Value used | Source | Last checked |
|---|---|---|---|
| Personal allowance | £12,570 | HMRC — Income Tax rates | May 2026 |
| Max transferable amount | £1,260 | HMRC — Marriage Allowance | May 2026 |
| Basic rate | 20% | HMRC — Income Tax rates | May 2026 |
| Basic rate upper threshold | £50,270 | HMRC — Income Tax rates | May 2026 |
Limitations
- Not available if either partner pays the additional rate (45%).
- Scottish higher rate taxpayers use a different scheme (Married Couple's Allowance via HMRC Scotland).
- Does not automatically calculate backdating amounts — multiply the annual saving by the number of eligible prior years (up to four) for an estimate.
Worked example
Partner A earns £9,000, Partner B earns £35,000.
Partner A has £3,570 unused allowance but maximum transfer is £1,260. Partner B's new allowance: £12,570 + £1,260 = £13,830 Partner B's tax saving: £1,260 × 20% = £252/year
Changelog
| Date | Change |
|---|---|
| May 2026 | Initial publication |