A second job is not taxed at a higher rate. Income tax is worked out on your total income across both jobs, so you pay the same tax as one job paying the combined amount. National Insurance is different: it is charged on each job separately, which usually means two jobs pay less National Insurance than one job on the same total. That split, one tax cumulative and one per employment, explains almost every question about second-job payslips.
The figures below use the 2026/27 rates for England, Wales and Northern Ireland.
Income tax: one allowance, shared across jobs
You get one personal allowance of £12,570 a year, whichever number of jobs you hold. HMRC gives it to one employer, normally your main job, through the 1257L tax code. The second employer is told to use code BR, which taxes every pound at 20% with no allowance, because the allowance has already been used elsewhere.
That is why the second payslip looks harsh. There is no tax-free slice, so £600 of second-job pay produces £120 of tax on the first payslip. It is not a higher rate, it is the normal basic rate applied without the allowance you have already had in the other job.
Take a main job at £20,000 and a second job at £8,000.
- Main job, code 1257L: £20,000 minus £12,570 is £7,430, taxed at 20%, which is £1,486.
- Second job, code BR: £8,000 at 20%, which is £1,600.
- Total income tax: £3,086.
One job paying £28,000 would be taxed on £15,430 at 20%, which is also £3,086. The tax is identical. The second job tax calculator runs the same comparison for any pair of salaries.
When the BR code goes wrong
BR is right only when the main job uses the whole allowance and the combined income stays below the higher rate threshold of £50,270. Two situations break that.
The main job pays less than £12,570. If the main job pays £10,000, £2,570 of allowance is wasted there while the second job is taxed on everything. HMRC can split the allowance between the jobs, for example code 1000L on one and 257L on the other, so that neither wastes it. You have to ask, through the HMRC app or the PAYE helpline; it does not happen automatically at the start of the year.
The combined income crosses £50,270. BR taxes the second job at 20% even when the total puts part of it into the 40% band. HMRC usually catches this in-year by changing the second job’s code to D0 (all at 40%) or by issuing a split code. If it is not caught, the shortfall appears on a P800 after the year ends and is collected through next year’s code. If your two jobs together exceed £50,270, check the codes early rather than waiting for the letter.
National Insurance: each job stands alone
National Insurance has no concept of total income. Each employer works out your contribution on the pay from that job only, against the same thresholds: 8% on pay between £1,048 and £4,189 a month, 2% above. Nothing is combined and nothing carries between employers.
Using the same figures:
- Main job, £20,000 a year, £1,667 a month: 8% of the £619 above £1,048 is £49.52 a month, or £594 a year.
- Second job, £8,000 a year, £667 a month: below the £1,048 threshold, so no National Insurance at all.
- Total National Insurance: £594.
One job at £28,000 pays 8% on the £15,430 above the annual threshold, which is £1,234. Holding the same income as two jobs saves about £640 a year in National Insurance. The saving is larger still for two part-time jobs that both sit under the threshold: two jobs at £12,000 each pay no National Insurance at all, while one job at £24,000 pays £914.
There is a cost to this. National Insurance contributions earn qualifying years towards the State Pension. Pay in a job has to reach the lower earnings limit, £129 a week (about £6,700 a year) in 2026/27, for that job to count, and each job is tested on its own. Two very small jobs that each fall short do not add together. The National Insurance calculator shows where a given monthly wage sits against the thresholds.
Student loans follow the National Insurance rule
Student loan deductions through PAYE also work per employment. Each employer compares that job’s pay with the plan threshold and deducts 9% of the excess. Two jobs that each pay under the threshold produce no deductions even if the combined income is well above it. On Plan 2 the threshold is £29,385 a year, or £2,448 a month; two jobs at £2,000 a month each attract nothing through payroll.
Unlike National Insurance, this can be corrected later, but only if you complete a Self Assessment return, where repayments are worked out on total income. Most employees with two PAYE jobs do not file one, so in practice the per-job rule stands. The student loan repayment calculator shows the deduction for each job separately.
Pensions, benefits and the other consequences
Auto-enrolment is assessed per job. Each employer enrols you only if that job pays at least £10,000 a year, so a second job under that figure will not come with a workplace pension unless you ask to join.
Universal Credit uses your combined earnings from all jobs in the assessment period, so the per-job treatment above does not help there. The Universal Credit calculator takes total earnings.
Tax-Free Childcare and Child Benefit are based on total adjusted net income, so two jobs count together.
Employer National Insurance is also per job, at 15% above £417 a month. This is one reason employers are comfortable with part-time roles that sit under the thresholds.
Telling HMRC and your employers
You do not have to tell your main employer about a second job, and HMRC will not tell them. The second employer needs the starter checklist, on which you select statement C, “I have another job”, so that BR is applied from the first payslip rather than an emergency code. HMRC learns about the second job from that employer’s payroll submission and adjusts codes if needed.
If your situation is more complex, a main job under the allowance, combined income over £50,270, or a job that ends part-way through the year, contact HMRC through the app so the codes are corrected in-year. Overpaid tax is refunded through your pay once a corrected code is in place; underpaid tax is collected through next year’s code.
Worked comparison: one job or two
| One job, £28,000 | Two jobs, £20,000 and £8,000 | |
|---|---|---|
| Income tax | £3,086 | £3,086 |
| National Insurance | £1,234 | £594 |
| Take-home | £23,680 | £24,320 |
The second arrangement leaves about £640 a year more in your pocket, entirely because of National Insurance. Whether the second job is worth it depends on the hours, the travel and the pension position, but the tax system itself does not penalise it. The take-home pay calculator gives the figure for each job, and the second job tax calculator shows the combined position.
Common questions
Is a second job taxed at 40%? Only if your combined income is above £50,270. Below that, a BR code taxes the second job at 20%, the same rate as the main job pays on income above the allowance.
Why is my second job on a BR code? Because your personal allowance has been given to your main job. BR means basic rate on everything, with no tax-free slice.
Do I pay National Insurance on both jobs? Each job is assessed on its own. You pay National Insurance in any job where the pay is above £1,048 a month, and none in a job below it, regardless of what the other job pays.
Can I split my personal allowance between two jobs? Yes. Ask HMRC and they will issue two codes that together add up to £12,570. This is worth doing when the main job pays less than the allowance.
Do I repay my student loan on a second job? Only if that job on its own pays above the plan threshold. Deductions are worked out per employment through PAYE.
Will my main employer find out about my second job? Not from HMRC. Tax codes are sent to each employer separately and do not reveal other employment.
Information, not financial advice. Figures are the published 2026/27 rates for England, Wales and Northern Ireland and are estimates to help you understand the rules. Check your own circumstances against gov.uk or with HMRC before acting on them.