Most people in the UK have no idea how much income tax they actually paid last year. The money is taken before it hits their bank account, and the payslip is the only place it shows up. That means small mistakes — a wrong tax code, an unclaimed allowance, a second job taxed the wrong way — can quietly sit there for years.
The good news is that HMRC now lets you check the full picture in about ten minutes. You do not need an accountant, and you do not need to call the helpline. You just need your National Insurance number and a little patience with the sign-in process.
Step 1: Sign in to your Personal Tax Account
Start at the GOV.UK Personal Tax Account page. If you have never used it, you will be asked to create a Government Gateway user ID or sign in through GOV.UK One Login. You will also need to pass an identity check using your passport, driving licence, or recent payslip.
Once you are in, you can see your income tax details, your tax code, your National Insurance record, and any benefits HMRC is tracking. Keep your sign-in details somewhere safe because you will use this account every time you need to check PAYE information.
Step 2: Look at your current tax year estimate
The first thing to check is the estimate for the current tax year. HMRC shows you how much income it thinks you will earn, the tax code being used, and how much tax it expects you to pay by 5 April.
If your pay has changed recently — a new job, a pay rise, a bonus, or a drop in hours — the estimate might be out of date. Compare it with your most recent payslip and with our UK salary calculator to see whether the figures still line up.
Step 3: Check previous tax years
You can see the last four tax years in the same account. For each year, HMRC tells you the income it has on record, the tax paid, and whether you overpaid or underpaid. If you overpaid, you can usually claim the refund online. If you underpaid, HMRC will normally collect it through a future tax code, but you can ask to pay it in one go.
Step 4: Cross-check with your P60 and payslips
Every April, your employer should give you a P60. This is the single most important tax document you receive each year. Line up the P60 figures with what HMRC has on record. If they do not match, the problem is often at the employer end and is easier to fix the sooner you spot it.
For a quick sense-check, try our tax code calculator. A tax code that is lower than the standard 1257L usually means HMRC has reduced your allowance for a reason, and it is worth knowing why.
What to do if you spot a mistake
If the tax paid does not match what you expected, do not panic. Common causes are a second job on the wrong code, underused allowances, work benefits that were never coded in, or a P45 that never reached payroll. You can message HMRC directly through your Personal Tax Account or call the helpline.
Keep a short written summary of what you found, with dates and figures, in case you need to refer back to it. A tidy paper trail is the quickest way to resolve a PAYE dispute.
The bottom line
Checking the tax you have paid is not meant to be a once-a-year job. Ten minutes every quarter will catch most problems long before they grow. The Personal Tax Account is free, official, and more accurate than any payslip summary, so there is no reason to leave your tax life in the dark.