Rates & sources
UK tax rates and thresholds, as published by HMRC. Scotland and Wales have devolved rates for income tax and property transactions.
Source: HMRC — Tax rates — figures refreshed at the start of each tax year.
When to use this calculator
- Before accepting a pay change, bonus, pension contribution, or salary-sacrifice option.
- When you want to compare employed, self-employed, or dividend-based income scenarios.
- When you need a simple take-home estimate before running payroll or filing returns.
- When you are approaching the £100,000 income level and want to understand the personal allowance taper effect.
- When you are planning a salary sacrifice arrangement and need to see the net pay impact before agreeing terms.
A realistic UK planning example
Use these sample inputs as a quick scenario test, then change one variable at a time to compare outcomes.
Lower Earner's Annual Income (£)
£35,000
Higher Earner's Annual Income (£)
£35,000
Backdate Claim (years)
Current year only
After entering these figures, review annual tax saving, total with backdating and allowance transferred together rather than in isolation — each metric tells a different part of the story. Then rerun the tool with one input adjusted to see which variable has the biggest effect on all three outputs before you settle on a plan.
How to read your results
Annual Tax Saving
Review this figure alongside your gross income so you can understand the true cost of deductions and plan around any thresholds before the tax year closes. If the figure looks higher than expected, check whether any pension or gift-aid contributions could reduce your taxable income.
Total with Backdating
This is the headline outcome of the calculation, but it is most useful when read alongside the supporting metrics below it rather than in isolation. Try changing one input at a time and watching how this total moves to understand which driver has the biggest impact.
Allowance Transferred
Use this metric to compare scenarios side by side and understand how changes in the key inputs drive the final outcome. If the figure surprises you, isolate one variable at a time and rerun the calculation to identify which assumption is responsible.
Method & assumptionsAuthoritative sources
This calculator checks eligibility for the UK Marriage Allowance using 2024/25 HMRC thresholds. The £1,260 transfer is available where the lower earner's income falls below the £12,570 personal allowance and the higher earner is a basic-rate taxpayer (income between £12,570 and £50,270). The annual saving is a fixed £252 — 20% of the transferred amount — because the relief only applies at the basic rate. The backdating feature multiplies the annual saving by the number of tax years selected, covering up to four complete past years plus the current year.
Eligibility is assessed on an all-or-nothing basis: if either income condition is not met, no saving is available. The calculator does not account for years where the higher earner may have paid higher-rate tax, or where other income sources such as rental or dividend income push adjusted income above £50,270. For borderline cases, pension contributions can reduce taxable income and restore eligibility. Always verify your position with HMRC's own eligibility checker before submitting a claim.
Common mistakes
- !Entering gross income when you really want take-home pay, or vice versa.
- !Ignoring pension contributions, deductions, or local tax rules that change the result.
- !Comparing monthly and annual figures without standardising them first.
- !Overlooking the National Insurance threshold changes that apply mid-year when rates or bands are adjusted in a Budget.
- !Assuming a salary sacrifice benefit reduces take-home pay by the full gross amount, rather than only the after-tax cost.
What to do next
- Check the same scenario with related pay or deduction calculators to see the full picture.
- Keep a copy of the assumptions you used so you can compare next tax year or pay period accurately.
- Read the related guides below if you are choosing between multiple income or deduction options.
- If you are self-employed, run the self-employment tax calculator alongside this result to compare the net position against employed income.
- Check whether increasing your pension contribution by even one or two percent changes the take-home significantly — use the pension calculator next.
Frequently asked
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End-of-article next steps
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