Emergency Tax Calculator United Kingdom

A first payslip on an emergency code can take far more tax than you expect. This calculator shows how much the code takes from your pay in 2026/27, how much Income Tax you actually owe on what you have earned so far and the refund the difference represents. Enter the gross pay on your payslip and pick the code printed next to it.

What an emergency tax code does

A normal tax code works cumulatively. Each payday your employer looks at your pay for the year to date, compares it with the allowance and bands you have built up to that point, and deducts the difference between the tax due and the tax already paid. That is what keeps PAYE accurate across a full year.

An emergency code breaks that link. Under 1257L on a Week 1 or Month 1 basis, each pay period is treated as if it were the first of the year. You get one twelfth of the personal allowance if you are paid monthly, or one fifty-second if paid weekly, and the matching slice of each band. Nothing carries forward. If you started work in month seven, the six months of unused allowance on your record are ignored and you pay tax you do not owe.

The four codes you are likely to see

1257L W1/M1 is the standard emergency code. It gives one period’s allowance, so you pay the right tax if you have worked the whole year and too much if you joined part way through.

BR stands for basic rate: every pound of that income is taxed at 20% with no allowance. It is correct on a genuine second job where your first job uses up your allowance, and badly wrong on your only job.

0T gives no personal allowance but applies the full set of bands, so pay is taxed at 20%, then 40%, then 45% as it rises through the per-period bands. Employers often use it when they have no starter information at all.

D0 taxes everything at the higher rate of 40%, and D1 at 45%. These appear when HMRC believes your other income already fills the lower bands.

How the calculator works out your refund

It compares two figures. The first is what the emergency code has taken: the tax on one pay period times the number of periods you have been on the code. The second is what a correct cumulative code would have charged on the same pay, using the allowance and bands built up to the pay period you have reached. A new starter often has no earlier income in the year, so the cumulative figure is usually much lower and sometimes zero.

The gap is your overpayment. On a £3,000 monthly salary, three payslips into a job started in month seven, a Month 1 code takes £390.50 a month, £1,171.50 in total, while the cumulative position is nil, so the whole amount is refundable.

How the money comes back

Usually automatically. Once HMRC issues the correct cumulative code to your employer, the next payslip recalculates the year and repays the excess in one go. If you give your employer a P45 or complete the HMRC starter checklist promptly, this normally happens within one or two pay runs.

If the tax year ends before the code is corrected, HMRC reconciles your record after April and issues a P800 calculation, then pays the refund by bank transfer or cheque. Pension withdrawals taxed under an emergency code are different: there may be no ongoing PAYE income to correct against, so you can reclaim with form P55, P53Z or P50Z instead of waiting.

What emergency tax does not change

National Insurance is worked out afresh for each pay period regardless of your tax code, so it is neither overpaid nor refunded because of an emergency code. Student loan deductions work the same way. Only the Income Tax line is affected.

Emergency tax on a pension withdrawal

The case that catches people hardest is not a new job. When you take your first flexible lump sum from a defined contribution pension, the provider usually has no code for you and applies an emergency code on a Month 1 basis. That treats a one-off withdrawal as if you would receive the same amount every month for a year, so a £30,000 payment is taxed as though your annual income were £360,000. The deduction can run to five figures.

The money is recoverable, though not always quickly. If the withdrawal emptied the pot, use form P50Z or P53Z; if it did not, form P55 gets the overpayment back within weeks instead of at the end of the tax year. Taking a small first withdrawal to trigger the correct code, then the main amount afterwards, avoids the problem.

Getting off the code faster

Give your new employer the P45 from your last job, or complete the starter checklist, choosing the statement that matches your situation. If a month passes with no correction, contact HMRC with your employer’s PAYE reference, which is on your payslip. Check your personal tax account online as well: an out-of-date estimate of your annual pay is a common reason a wrong code persists.

These figures are an estimate based on the 2026/27 allowance, bands and National Insurance thresholds, and assume level pay with no other income in the tax year. Your actual code depends on your full HMRC record, so treat this as a guide rather than tax advice and check your payslip and personal tax account for the definitive position.

About This Emergency Tax Calculator

Use this emergency tax calculator to get an instant, accurate estimate. The figures follow official GOV.UK guidance and every rate and threshold is kept up to date for 2026. Adjust the inputs above to match your situation, or browse all our calculators to plan your next step.