See what a second job costs in tax and National Insurance, why the BR tax code is not a penalty, and when PAYE under-collects.
A second job is usually taxed under a BR code, which takes basic rate from every pound of it. That looks punitive but it is not: while your combined income stays within basic rate you pay exactly the same income tax as you would earning the same total in one job. National Insurance is where the two genuinely differ, because it is worked out separately for each employment.
On £35,000 a year, a standard 2026/27 tax code and no pension or student loan, the figures work out like this. Open a calculator to put your own numbers in.
Each row runs the same engine twice, once per employment, and compares it against earning the identical total in a single job. The second job is on a BR code throughout.
| Main job + second job | Take-home across both | National Insurance kept | Income tax deferred |
|---|---|---|---|
| £20k + £5k | £21,920 | £400 | none |
| £25k + £8k | £27,920 | £640 | none |
| £30k + £8k | £31,520 | £640 | none |
| £38k + £10k | £38,880 | £800 | none |
| £45k + £10k | £43,920 | £516 | £946 |
| £60k + £20k | £60,763 | -£194 | £4,000 |
The National Insurance column is a real difference you keep, because each employment is assessed against its own thresholds. The deferred column is not a saving: it is what a basic rate code fails to collect once combined income reaches higher rate, and HMRC reclaims it later.
This compares PAYE deductions across two jobs against the same total in one job. It does not decide your tax code, and it cannot see what HMRC has already allocated between your employments.
A second job is usually taxed under a BR code, which takes basic rate from every pound of it. That looks punitive but it is not: while your combined income stays within basic rate you pay exactly the same income tax as you would earning the same total in one job. National Insurance is where the two genuinely differ, because it is worked out separately for each employment.
| Tax/source year | 2026/27 |
|---|---|
| Region | England/Wales/Northern Ireland |
| Tax code basis | 1257L where the page uses PAYE defaults |
| Pension basis | No pension deduction unless this example says otherwise |
| Student loan basis | No student loan unless selected in this example |
| What is not decided here | PayBreakdown does not decide payroll correctness, lender approval, benefit entitlement or employer compliance, and does not give regulated financial, mortgage, debt, tax, payroll or legal advice. |
|---|
The figures on this page use the values below. Open the calculator if your example salary differs.
BR means all income from that job is taxed at the basic rate, because your Personal Allowance is already being used by your main job. Applying it once, in one place, is the point.
This is the part that genuinely changes your take-home. Each employer runs National Insurance against its own thresholds rather than against your combined earnings.
A basic rate code on the second job cannot know your combined income. Once the total crosses the higher rate threshold, the second job is under-taxed during the year and HMRC reclaims the difference afterwards.
A second job is usually taxed under a BR code, which takes basic rate from every pound of it. That looks punitive but it is not: while your combined income stays within basic rate you pay exactly the same income tax as you would earning the same total in one job. National Insurance is where the two genuinely differ, because it is worked out separately for each employment. Salary estimates can change when the tax year, UK region, tax code, pension method, student loan plan, pay frequency, bonus, overtime or salary-sacrifice assumptions change.
The useful figure for budgeting is usually take-home pay after Income Tax, National Insurance, pension deductions and student loan deductions. Gross pay helps compare jobs, while net pay is usually the better starting point for bills, savings and borrowing checks.
Real payslips can differ because payroll works by pay period and can include tax-code changes, pension method differences, student-loan starts or stops, taxable benefits, salary sacrifice, bonuses, overtime, arrears, refunds, or rounding. Match the calculator settings to the payslip before treating a difference as meaningful.
Two jobs with the same headline salary can feel different once pension contribution rate, employer pension method, student-loan plan, bonus pattern, overtime, tax code, region, salary sacrifice and pay frequency are considered. Compare the monthly net figure with commuting costs, bills and savings goals before deciding whether a higher gross salary improves the household plan.
Start by matching the pay basis: annual salary, hourly rate, weekly hours, pay frequency and whether the figure is full-year or part-year. Then match the deductions that usually move the result the most: pension method, pension rate, student-loan plan, postgraduate loan, tax code, Scottish or Welsh tax treatment, bonus, overtime, taxable benefits and salary sacrifice. If the page is a comparison page, keep both sides on the same tax year and pension method before reading the difference. If it is a required-salary or pro-rata page, treat the answer as a target estimate and rerun it with a cautious lower-income or higher-deduction scenario before using it for bills, rent, borrowing or savings.
Use the visible result as a starting point, then change the assumptions that apply to your situation. For salary pages, that usually means tax year, region, tax code, pension method, student loan plan, bonus, overtime and salary-sacrifice settings. For borrowing, debt or budget pages, it means the real payment amount, term, interest rate, balance, bill timing, savings target and any expected income change. Keep the result separate from advice or approval decisions: PayBreakdown helps you model the numbers, while official sources, employer records, provider documents and professional support are still the right place for final checks. If a change is close to a threshold, rerun the calculation with a cautious higher-cost or lower-income scenario before relying on the result.
Not while your combined income stays within basic rate. A BR code taxes the whole second job at 20% because your Personal Allowance is already used by the first job, and that comes to the same income tax you would pay earning the same total in one job.
BR means all income from that job is taxed at the basic rate. It is applied because your tax-free Personal Allowance has already been allocated to your main employment, so there is none left to set against the second job.
You pay it separately on each job, which is not the same as paying twice. Each employment is assessed against its own thresholds, so a second job below the threshold pays no National Insurance at all, and two jobs on the same total often pay less than one job would.
You can, if your combined income crosses the higher rate threshold while the second job is still on a basic rate code. PAYE then collects too little during the year and HMRC reclaims the difference, usually through a tax calculation or a changed code.
Last updated 2026-08-19. Estimates are for planning and should be checked against official records where the decision matters.