Second Job Tax Calculator UK

Find out how much tax you will pay on a second job and what take-home pay you can expect for the 2025/26 tax year.

How Are Second Jobs Taxed in the UK?

When you take on a second job in the UK, the way income tax works changes significantly. Your Personal Allowance — the amount you can earn tax-free (£12,570 for 2025/26) — is almost always allocated entirely to your main job. This means your second job income is taxed from the very first pound using one of two specialist tax codes.

HMRC uses the BR tax code (Basic Rate) for most second jobs. Every penny earned from that job is taxed at 20%. If your combined income from both jobs pushes you into the higher rate band (above £50,270 in total), HMRC will switch your second job to the D0 tax code, which taxes all second job earnings at 40%.

The Personal Allowance and Your Main Job

The Personal Allowance of £12,570 means the first £12,570 of your income is tax-free. Because this is allocated to your main job, by the time you start earning from a second job, you have already used your allowance. There is no additional tax-free amount for a second or third job.

For the 2025/26 tax year, the income tax bands are:

Understanding Tax Code BR

The BR tax code is assigned when HMRC knows you have a main employment that already uses your Personal Allowance. BR stands for "Basic Rate" and means 20% tax is deducted on all earnings from that job, with no allowances applied. This is the correct code for most people with a second job whose total income remains below £50,270.

Understanding Tax Code D0

The D0 tax code is used when all income from the second job should be taxed at the higher rate of 40%. This applies when the main job salary already exceeds the basic rate band limit (£50,270). For example, if your main job pays £55,000, your second job income all falls within the higher rate band, so HMRC assigns D0.

Worked Example: Main Job £30,000, Second Job £10,000

National Insurance on a Second Job

National Insurance Contributions (NICs) are calculated separately for each employment. Each job is treated as its own NI calculation. For 2025/26, Class 1 employee NICs are:

• 0% on earnings up to £12,570 per year (the Primary Threshold)
• 8% on earnings between £12,570 and £50,270
• 2% on earnings above £50,270

Because NI is calculated per employer and not aggregated, you may actually pay less NI across two jobs than you would if all that income came from a single employer. For example, if your second job pays £8,000 per year, which is below the NI Primary Threshold of £12,570, you pay no NI at all on your second job earnings.

If you have multiple jobs and end up overpaying NI (which can happen when combined earnings exceed £50,270 but you have paid at 8% on each job separately), you can claim a refund from HMRC. This is processed through your annual tax calculation.

Pension Auto-Enrolment on a Second Job

Auto-enrolment rules apply separately to each employment. If your second job earnings exceed the earnings trigger (£10,000 per year in 2025/26), your second employer must automatically enrol you into a workplace pension. You can opt out if you choose. If your second job pays below £10,000 annually, you may ask to join but the employer is not obliged to enrol you automatically.

The minimum contributions are 5% employee and 3% employer on qualifying earnings (between £6,240 and £50,270). Consider whether pension deductions from a second job are worth it given your overall retirement savings strategy.

Self-Employment as a Second Income

If you are employed in your main job and also run a self-employed side business, the rules differ from a straightforward second job:

• Income Tax: Both employed and self-employed income are combined for income tax purposes. You complete a Self Assessment tax return each year.
• Class 1 NI: Paid via PAYE on your employment income.
• Class 2 NI: Flat rate of £3.45 per week if self-employed profits exceed £12,570.
• Class 4 NI: 9% on self-employed profits between £12,570 and £50,270, and 2% above £50,270.
• Expenses: You can deduct allowable business expenses from self-employed income before calculating tax.
• Trading Allowance: If self-employed income is £1,000 or less per year, you do not need to register for Self Assessment.

Tax Codes: Cumulative vs Non-Cumulative

There are two types of tax codes:

• Cumulative: HMRC looks at your total earnings and tax paid from the start of the tax year to work out what you owe. Most main job tax codes are cumulative.
• Non-cumulative (Week 1/Month 1 basis): Each pay period is taxed in isolation, without reference to previous pay periods. This is sometimes applied to second jobs or when starting a new job mid-year. You may see "W1" or "M1" added to a tax code.

If you believe you are on the wrong tax code, contact HMRC on 0300 200 3300 or update your details via the HMRC Personal Tax Account online.

Getting a Tax Rebate at Year End

If you have been taxed too much on a second job — for example, if BR was applied when you should have had some allowance, or if you stopped the second job partway through the year — you may be owed a refund. HMRC automatically issues a P800 notice after the tax year ends (usually between June and November). If you are owed money, you can claim it via your Personal Tax Account or wait for a cheque to arrive by post.

You can also contact HMRC in-year if you believe your tax code is wrong, and they can adjust it so you pay the right amount going forward rather than waiting for a year-end rebate.

How to Ensure You Have the Correct Tax Code

1. Check your payslip — the tax code should be printed on every payslip.
2. Log in to the HMRC Personal Tax Account at gov.uk/personal-tax-account to see all your tax codes.
3. If your second job is coded as BR and you believe you have allowances available, contact HMRC to request a review.
4. When starting a new second job, complete the Starter Checklist (formerly P46) and declare it is not your only job. This ensures the employer uses BR rather than the emergency 1257L cumulative code, which could lead to under-taxation and an unexpected bill later.

Frequently Asked Questions