How to Check How Much Tax You Owe HMRC Online (2025-26)
HMRC's Personal Tax Account gives you a real-time view of your tax position — including any outstanding amounts, your current tax code, employment history, and National Insurance record. Most people can access everything they need in a few minutes without calling HMRC at all.
Accessing your Personal Tax Account
Go to gov.uk/personal-tax-account and sign in with your Government Gateway credentials. If you do not have a Government Gateway account, you can create one using your National Insurance number and a form of ID (passport or driving licence). You can also sign in using the HMRC app, available on iOS and Android.
What you can see in your Personal Tax Account
- Current tax code: see what code your employer is using and whether it is correct
- Tax estimate for the current year: HMRC's estimate of whether you owe or are owed a refund
- Employment and pension income history: records going back several years
- National Insurance record: qualifying years, gaps, and State Pension forecast
- Benefits claimed: Child Benefit, Marriage Allowance, and others
- Previous tax years: P60-equivalent information
The P800: HMRC's end-of-year tax calculation
After the tax year ends, HMRC reviews PAYE taxpayers' accounts and issues a P800 if you have paid too much or too little tax. If you are owed a refund, HMRC will usually pay it automatically. If you owe tax, it will typically be collected by reducing your tax code in the following tax year — spreading the repayment over 12 months rather than requiring a lump sum payment.
Underpaid tax: what happens
If HMRC calculates that you underpaid tax in a previous year, the standard approach is to collect the underpayment through your PAYE tax code. A tax code reduction of, say, 200 points (e.g., from 1257L to 1057L) reduces your personal allowance and therefore collects approximately £400 in extra tax from a Basic Rate taxpayer over the year. HMRC must notify you before adjusting your code.
Self Assessment: a different system
If you are registered for Self Assessment, you calculate your own tax liability and pay it directly rather than relying on PAYE. Your Personal Tax Account shows your Self Assessment balance and payment history. Any balance due for 2024-25 was payable by 31 January 2026. Payments on account for 2025-26 were due 31 January 2026 and 31 July 2026.
Checking your National Insurance record
Your NI record shows how many qualifying years you have accumulated toward the full New State Pension. You need 35 qualifying years for the full amount (£221.20/week in 2025-26). Gaps can often be filled voluntarily — check your forecast and consider whether topping up gaps is cost-effective before the deadline.
Frequently asked questions
How long does it take for HMRC to update my account after a job change?
HMRC receives Real Time Information (RTI) submissions from employers on or before each payday. Updates to your Personal Tax Account typically appear within a few days to a few weeks, depending on when your employer files and when HMRC processes the data.
Can I dispute my tax code through the Personal Tax Account?
Yes. If your tax code looks wrong — perhaps it is reflecting a benefit you no longer receive or an underpayment from a job you left — you can contact HMRC directly through the account to request a review.