P800 Tax Checker, 2026/27
HMRC issues a P800 when the tax deducted through PAYE across the year does not match what was actually owed. This checker reproduces that reconciliation so directors and employees can see if a refund or a bill is likely.
The p800 tax checker runs on the rates and thresholds HMRC has published for the 2026/27 tax year, so the figures you see reflect the position your company is actually filing on rather than a historic set of bands. Change any input and the result recalculates immediately, with no sign-up and nothing sent anywhere.
If you are a director of a UK limited company, use it as a first look before a decision rather than as the decision itself. Uses the standard 2026/27 personal allowance, basic and higher rate bands, and the dividend allowance and rates. Real company positions bring in other income, reliefs, group structures and prior year adjustments that a single page of inputs cannot see, which is why the workings are written out below under personal & self assessment tax. Read those, then check the numbers against your own accounts, and speak to us if anything looks materially different from what you expected.
Last reviewed 12 September 2026 for the 2026/27 tax year. Reviewed by Waqas Sagar, Member of ICAEW, Fellow of ACCA, Fellow of AAT.
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Result, 2026/27
Estimated refund due
Tax actually due for the year
Tax deducted through PAYE
Effective tax rate
Illustration only, figures are based on the rates you have selected and the information entered. Please check your own position with us before acting.
Estimates for the 2026/27 tax year using published GOV.UK rates. Switch between 2026/27 and 2025/26 above.
How this is calculated
This checker calculates the income tax that should be due on your total employment and dividend income for 2026/27, using the £12,570 personal allowance (tapered above £100,000), the 20% basic rate band up to £37,700 of taxable income, the 40% higher rate band up to £125,140, and 45% above that, together with the £500 dividend allowance and the dividend rates.
It then compares that figure to the tax actually deducted from your pay through PAYE across the year. A shortfall suggests HMRC may issue a P800 asking for more tax; a surplus suggests a refund is likely, subject to the fuller checks HMRC runs.
This is a simplified version of the real P800 process: HMRC's calculation also reconciles month-by-month tax code changes, benefits in kind reported on a P11D, and any other income HMRC already knows about.
Why P800s happen
A mismatch commonly arises from a mid-year tax code change, starting or leaving a job partway through the year, having more than one PAYE source at once, or a benefit in kind being coded incorrectly.
Directors who also draw dividends often see a P800-style shortfall because PAYE only ever collects tax on salary, never on dividends, so the dividend tax has to be settled separately through self-assessment rather than through a P800 at all.
What to do next
If HMRC sends a genuine P800 showing a refund, it is usually paid automatically or claimable online. If it shows an underpayment, HMRC typically collects it by adjusting next year's tax code rather than demanding a lump sum, unless the amount is large.
If you already complete a self-assessment return, HMRC does not normally issue a P800 at all, since the annual return itself performs this reconciliation.
What this means for your company
Treat the result as a planning figure for the 2026/27 tax year. If it changes what you were about to do, take a director's salary, a dividend, a large asset purchase or a filing decision, check it against your own accounts first. We can review the position with you and confirm the tax treatment before you commit.
Frequently asked questions
What is a P800?
A P800 is a tax calculation letter HMRC sends when the tax collected through PAYE across a year does not match what you actually owed, showing either a refund or an amount still due.
Will I get a P800 automatically if I am owed a refund?
HMRC's own systems normally trigger a P800 automatically once their end-of-year reconciliation runs, usually between June and October after the tax year ends, but it is worth checking rather than waiting if you suspect an overpayment.
Does a P800 cover dividend income?
No. P800s only reconcile PAYE income such as salary, pensions and taxed benefits. Dividend tax and other untaxed income are dealt with through self-assessment instead.
What if I disagree with a P800 figure?
You can query it with HMRC and provide evidence such as final payslips or P45s. Errors often arise from an employer reporting benefits late or a tax code not updating in time.
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