Two jobs tax calculator

How it works

When you have more than one job, each employer runs its own payroll. Neither knows what the other pays you, so HMRC gives each job its own tax code to make sure the right total tax is collected. This calculator works out each job the way its payroll would, then adds them up.

Income tax

Your Personal Allowance of £12,570 normally goes to your main job, which gets the standard code 1257L. Your second job then usually has a BR code, so all of its pay is taxed at 20%. If your total pay takes you over the higher-rate threshold of £50,270, HMRC may use D0 (40%) on the second job instead. In Scotland the codes start with S and use Scottish rates.

Problems happen when the codes don’t match your real pay. If your main job pays less than the allowance, some of it goes unused while the BR job still pays 20% on everything, so you overpay. If both jobs use 1257L, you get the allowance twice and underpay. The calculator compares the tax your codes collect with the tax due on your combined pay and shows the difference.

National Insurance

National Insurance is worked out for each job on its own. You pay 8% only on the pay in each job above £12,570 a year, so two smaller jobs can mean less National Insurance than one job paying the same total. Unlike income tax, there’s nothing to “correct” at the end of the year.

Student loans

Student loan repayments are also worked out per job, against the full threshold in each. If neither job on its own pays over the threshold, nothing is deducted, even if your combined pay is above it.

How to fix a wrong tax code

Check your tax codes on your payslips or in your personal tax account on GOV.UK. If your main job doesn’t use all of your Personal Allowance, you can ask HMRC to give the unused part to your second job, which lowers the tax taken there. If the calculator shows you’re underpaying, it can be better to ask HMRC to adjust your codes now than to face a bill after the tax year ends.

The same applies if one of your incomes is a pension: the pension payer runs PAYE just like an employer, and its tax code needs to fit with your other income. If you stop one job, tell HMRC so they can move your allowance back.

Rates verified against HMRC on 5 October 2026.

Worked example

You earn £40,000 in your main job (1257L) and £15,000 in a second job (BR). Income tax is £5,486.00 plus £3,000.00 = £8,486.00. One job paying £55,000 would pay £9,432.00, so you’re underpaying about £946 a year: part of the second job should be taxed at 40%.

Two jobs of £10,000 each the other way round overpay by about £514, because £2,570 of the allowance is unused in the main job.