Tax Refund Estimator: Check What You Could Be Owed

Start with the estimator above

Pop your gross pay and the tax actually taken (both shown on your payslip or P60) into the calculator at the top of this page. The tax refund estimator subtracts the tax you should have paid from the tax you did pay. If the result is positive, that gap is the refund you could reclaim from HMRC.

How the tax refund estimator works

A refund happens when the tax deducted from you over the year is more than your actual liability. The maths is simple in principle:

Estimated refund = Tax paid during the year − Tax actually due on your income

To find the tax actually due, the tool applies the 2026/27 rules. Everyone gets a tax-free Personal Allowance of £12,570 (unless income tops £100,000, where it tapers away by £1 for every £2 over, reaching zero at £125,140). Income above the allowance is taxed at 20% up to £37,700 of taxable income, 40% from there to £125,140, and 45% above that. So the calculation is:

• Work out taxable income: gross income minus your Personal Allowance.
• Apply 20%, then 40%, then 45% to each slice that falls in that band.
• Compare that figure with the tax your employer or pension actually deducted.

Because PAYE spreads your allowance evenly across 12 months, problems appear when something changes mid-year: you leave a job, start a new one, get the wrong tax code, or stop working partway through. The system can take too much, and that surplus sits with HMRC until you claim it or it reconciles at year end. If you are in Scotland, the band rates differ (a starter, basic, intermediate, higher, advanced and top rate apply instead of the rest-of-UK structure), so a Scottish taxpayer should treat the headline figure as a rough guide and check with our Scotland tax calculator.

Worked example: a nurse who left mid-year

Priya earns £30,000 a year and is paid £2,500 a month. Her tax code spreads the £12,570 allowance evenly, so each month around £1,047 of pay is tax-free and the rest is taxed at 20%. She pays roughly £291 income tax a month.

Priya stops work at the end of September, six months into the tax year. Her total pay for the year is £15,000. The tax actually due is: £15,000 − £12,570 = £2,430 taxable, × 20% = £486. But she already paid about £291 × 6 = £1,746 through PAYE. Her estimated refund is £1,746 − £486 = £1,260. That money is hers because PAYE assumed she would keep earning all year and use less of her allowance each month than she actually did.

Worked example: emergency tax on a new job

Tom starts a new role on £42,000 but his P45 is delayed, so he is put on an emergency code and taxed without his full allowance for two months. He is overtaxed by roughly £400 across those payslips. Once his correct code is applied his future pay corrects, but the £400 already overpaid only comes back through a refund or year-end reconciliation. If this sounds familiar, our emergency tax calculator shows exactly how the temporary code inflates your deductions.

Worked example: unclaimed work expenses

Sam, a basic-rate taxpayer, drives 6,000 business miles a year in her own car and is reimbursed nothing. HMRC's approved mileage rate lets her claim tax relief on 45p per mile for the first 10,000 miles: 6,000 × 45p = £2,700 of allowable expense. As a 20% taxpayer that is worth £2,700 × 20% = £540 back per year. Claim four years and that is over £2,000. The work expense tax rebate calculator breaks this down by expense type.

2026/27 income tax rates used by this estimator

These are the rest-of-UK figures the estimator applies. Always confirm your own position against the official source.

Source: gov.uk income tax rates, checked for the 2026/27 tax year. You can also view your own records and ask for a refund through your Personal Tax Account on gov.uk.

How far back can you claim?

You can reclaim overpaid tax for the current year and the four previous tax years. For 2026/27 that means you can generally still claim back to the 2022/23 year, but each year has its own deadline of 5 April four years on, so older claims expire first. If you think several years are affected, start with the oldest before it drops off the edge. Our tax rebate checker helps you scan year by year.

How to actually claim your refund

• Check your tax code first. A wrong code is the most common cause of overpayment. Compare yours against the standard 1257L using our tax code checker.
• Use your Personal Tax Account for PAYE overpayments. HMRC often issues a P800 calculation after the tax year ends; if it shows a refund you can claim it online.
• Claim job expenses (uniforms, tools, professional fees, mileage) through the gov.uk employment expenses service or a Self Assessment return.
• Transfer Marriage Allowance. A non-taxpaying spouse can transfer £1,260 of Personal Allowance to a basic-rate partner, and the claim can be backdated four years.

Common mistakes that cost people refunds

• Assuming PAYE always gets it right. It usually does over a full, stable year, but job changes, multiple jobs and benefits-in-kind throw it off.
• Using a refund company that takes a big cut. Claiming directly through gov.uk is free; some agents keep 30% or more of your money.
• Forgetting savings interest. The Personal Savings Allowance gives basic-rate taxpayers £1,000 of tax-free interest (£500 for higher-rate), so tax wrongly taken on small interest may be reclaimable.
• Missing the four-year window. Each year's deadline passes quietly; a 2022/23 claim must be in by 5 April 2027.
• Treating the estimate as final. This figure ignores items like student loan deductions and some benefits, so use it to decide whether to dig deeper.

If you would rather sanity-check the underlying tax figure, our income tax calculator shows the full breakdown for any salary.

This tool gives estimates for guidance only and is not personal tax or financial advice. Figures depend on your full circumstances; confirm any refund with HMRC before relying on it.

Who should use this calculator

Produces a figure rather than a yes-or-no, which is what you want when deciding whether a claim is worth the effort. For a small over-deduction the answer may be to leave it for HMRC’s year-end reconciliation; for a larger one it is worth claiming actively.

Set expectations on timing: a P800 calculation after year end usually arrives between June and October, and an active claim typically takes a few weeks. Anything promising an instant refund for a fee is a commercial service taking a cut of your own money.

What this calculator assumes

• The estimate compares tax actually deducted against tax properly due on the year’s figures.
• The Personal Allowance is applied as an annual entitlement.
• Only Income Tax is estimated.
• Scottish rates apply where selected.

Limitations — what it does not cover

• HMRC’s own reconciliation, which often issues a P800 automatically without any claim.
• Offsetting underpayments from other years, which reduce what is actually paid out.
• Benefits in kind and other income collected through your code.
• Processing time, and the security checks HMRC applies to larger refunds.
• Bank details, needed for payment — HMRC never asks for them by text or email.
• The four-year limit.

Related calculators

Carry on with a few tools that pair well with this one: the tax refund calculator for a fuller breakdown, check if HMRC owes you money to scan common refund triggers, and the marriage allowance calculator if you are married or in a civil partnership.