Two jobs
2026-27How this is worked out
The three things taken off your pay disagree about what a second job is, and that is the whole of what makes two jobs confusing.
Income Tax is charged on the total, once
Your liability for the year is worked out on everything you earned, added together. But your employers deduct what your tax codes tell them to, job by job, and neither of them can see the other. With a normal pairing — the allowance on the first job and BR on the second — the two deductions usually come close, and with anything unusual they do not. HMRC settles the difference afterwards, which is the letter people are surprised by. Both figures are shown above because both are real: one is what leaves your payslips, the other is what you owe.
⚠ National Insurance is charged on each job separately
And each employment gets its own threshold. Someone earning £24,000 across two jobs can pay a fraction of the National Insurance of someone earning £24,000 from one, because each job spends part of its pay below the threshold. It is not avoidance and it is not a loophole — Class 1 National Insurance is defined per employment, per pay period. It is also why taking a second job can leave you better off than a raise of the same size.
The exception: where two employers are carried on in association — broadly, run by the same people — the earnings are added together and there is only one threshold. This assumes two unconnected employers.
A student loan works the same way
Repayments are assessed per employment for PAYE, so two jobs that are each under the repayment threshold repay nothing, on income that would repay plenty from one payslip. If you also file a Self Assessment return, the total is looked at again there.
What this does not cover
It assumes both jobs are employments taxed under PAYE, paid monthly and evenly through the year, from unconnected employers, and that neither started or ended part-way through. It does not handle pension contributions, benefits in kind, self-employment alongside a job, or a code operated on a week 1 / month 1 basis.
Where these rates come from
Every figure above is read from a dated rate file rather than written into the page, and each entry records the gov.uk page it came from. See Income Tax rates and Personal Allowances, rates and thresholds for employers and repaying your student loan on gov.uk. How these numbers are kept right sets out the whole process.