Second Job Emergency Tax Code UK 2026/27: How to Fix It

Why Does My Second Job Have a Different Tax Code?

Starting a second job in the UK often produces an unpleasant surprise on your first payslip: a code like BR or D0 and tax taken at 20% or 40% from the very first pound. It looks like HMRC is penalising you for working harder. In fact it is the result of a logical -- if frustrating -- feature of how PAYE works.

Every UK taxpayer has a Personal Allowance. In 2026/27 that is GBP 12,570 of income you can earn completely free of income tax. HMRC assigns that allowance to one employer at a time, usually through your tax code. A standard code like 1257L tells your employer to treat the first GBP 12,570 you earn as tax-free and deduct 20% on anything above it (up to the higher-rate threshold).

When you start a second job, your Personal Allowance is already spoken for. Your second employer has no authority to apply it again. HMRC instructs them to deduct tax from every pound instead. The code they use depends on what HMRC believes your marginal rate is.

The BR Code Explained

BR stands for Basic Rate. Under this code your second employer deducts 20% from every pound you earn in that job -- no personal allowance, no nil-rate portion, just a flat 20%.

This sounds harsh but is arithmetically correct for most people. Here is why:

Your first job uses your GBP 12,570 allowance. Income above that, up to GBP 50,270, is taxed at 20% basic rate. When you add second-job income on top, it starts at whatever point your first job reaches -- so if your first job pays GBP 25,000, your second-job income starts at GBP 25,000 in the cumulative stack. Every pound of second-job income falls in the basic-rate band and should be taxed at 20%. BR achieves exactly that.

Where BR causes a problem is when your combined income is so low that some second-job income should actually be tax-free. For example, if your first job pays GBP 8,000 (below the GBP 12,570 threshold) and your second job pays GBP 5,000, you have GBP 13,000 total -- only GBP 430 above the Personal Allowance. But BR would tax all GBP 5,000 from the second job. You would overpay significantly and need a refund. This is exactly the scenario where contacting HMRC to split the allowance between employers makes sense.

The D0 Code and When It Applies

If HMRC believes your first-job income already takes you above GBP 50,270 -- the higher-rate threshold in 2026/27 -- it will give your second employer a D0 code. D0 deducts 40% from every pound, again with no tax-free amount.

This applies when:

• Your primary job salary exceeds GBP 50,270, OR
• Your primary job income plus other income (for example rental income or freelance earnings) already fills the basic-rate band

There is also a D1 code that applies 45% additional rate for people whose first-job income already exceeds GBP 125,140. At that level the Personal Allowance has been fully tapered away (it reduces by GBP 1 for every GBP 2 of income over GBP 100,000 and is gone entirely at GBP 125,140) and the marginal rate on extra income is 45%.

D0 is not a punishment -- it reflects your real marginal rate. But it is frequently applied in error because HMRC is working from estimated income data. If your first job pays GBP 45,000 and HMRC incorrectly codes your second job D0, you are overpaying 40% instead of the correct 20%. You will get a refund eventually but you have lost the use of that money during the year.

How to Check Your Tax Code Is Correct

Your tax code appears on:

• Your payslip (usually a letter/number combination)
• Your P60 at year end
• Your HMRC Personal Tax Account at gov.uk

To check whether BR or D0 is correct for your situation, you need to know:

1. Your expected annual earnings from your primary job in 2026/27
2. Your expected annual earnings from your second job
3. Any other taxable income (rental income, freelance income, savings interest over the GBP 500 savings allowance)

Add them all together. If the total is below GBP 50,270, your second-job marginal rate should be 20% -- BR is correct. If the total is above GBP 50,270, some or all of your second-job income falls in the higher-rate band -- D0 may be wholly or partially correct.

Use the CalcHub Take-Home Pay Calculator to enter both income streams and see the correct combined tax figure. Then compare it with what is actually being deducted across both payslips. Any gap is an overpayment or underpayment that needs addressing.

How to Fix the Wrong Tax Code

Step 1 -- Complete a new starter checklist. When you start a second job your new employer should ask you to complete a starter checklist (the digital replacement for the old P46 form). There are three statements on the form:

• Statement A: This is your only job
• Statement B: You have another job or pension
• Statement C: You have another job and a pension

For a second job you should tick Statement B or C. If you tick Statement A by mistake, your employer may apply the wrong code -- sometimes 1257L, meaning your Personal Allowance is applied twice, causing you to underpay tax and face a year-end bill.

Step 2 -- Contact HMRC. If you are already in the wrong code, call HMRC on 0300 200 3300 (Monday to Friday, 8am to 6pm) or update your details via your Personal Tax Account online. Have both employers' PAYE references and both income estimates to hand. HMRC will issue a revised tax code to the relevant employer, usually taking effect within a few weeks.

Step 3 -- Ask your employer to apply the new code. Once HMRC issues an updated code your employer should implement it in the next payroll run. If you believe there has been a delay, show your payroll department the letter or online notification from HMRC.

What Happens at Year End

Even if nothing is corrected during the year, HMRC reconciles your total income and tax paid after 5 April each year. If you have overpaid, you normally receive a P800 letter between June and November telling you the amount overpaid and how to claim it.

For 2026/27 (tax year ending 5 April 2027) you would typically receive your P800 by autumn 2027. You can claim the refund online through your Personal Tax Account, by cheque, or bank transfer. If HMRC does not contact you but you believe you have overpaid, you can contact them directly or, if you are in self-assessment, the overpayment appears as a credit on your tax return.

If you have underpaid -- for example because you ticked Statement A by mistake and your Personal Allowance was applied by both employers -- HMRC will send a Simple Assessment or P800 showing the amount owed. You can pay by direct debit, debit card, or HMRC may collect it through your PAYE code the following year by reducing your tax-free amount.

National Insurance on a Second Job

Income tax is not the only thing to consider. National Insurance Contributions (NIC) are also deducted on each job separately. In 2026/27:

• Employee NI is 8% on earnings between GBP 12,570 and GBP 50,270 per year (GBP 1,048/month lower threshold)
• Employee NI is 2% on earnings above GBP 50,270

Crucially, the primary threshold applies per employment, not in aggregate across all jobs. So if your second job pays GBP 15,000 per year, your second employer deducts 8% NI on the portion above GBP 12,570 -- meaning GBP 2,430 of earnings at 8%, adding GBP 194 in extra NI per year.

There is no automatic NI reconciliation equivalent to the P800 process for income tax. If you overpay NI across multiple jobs (because each employer applies the thresholds independently), you can claim a refund from HMRC using the CF83 process or by writing to HMRC after the tax year ends. Over-deduction is common for second jobs that pay above the primary threshold -- worth checking if your second job earns more than GBP 12,570.

Self-Employment as a Second Income

If your second income comes from self-employment rather than a second PAYE job, the picture changes. Self-employment income is reported on a self-assessment tax return. There is no second employer applying an emergency code -- instead you calculate your own tax bill annually.

However, you do need to register for self-assessment if your self-employment income exceeds GBP 1,000 per year (the trading allowance). Tax on self-employment income above GBP 1,000 is due by 31 January after the tax year ends, with a payment on account due the following 31 July. If your PAYE job already uses your Personal Allowance, all self-employment profit above the GBP 1,000 trading allowance is taxable at your marginal rate from pound one -- the same effect as a BR code but handled through self-assessment instead of PAYE.

Use the CalcHub Self-Employed Tax Calculator to estimate your self-assessment bill alongside your employed income.

Tips for Managing Two Jobs Efficiently

• Keep both payslips and check the cumulative tax figures each month, not just the monthly deduction
• Log into your HMRC Personal Tax Account at least once per quarter to check your tax code and estimated annual income figure are correct
• If you leave the second job mid-year, ask for a P45 immediately -- this allows HMRC to reconcile and issue a refund faster
• If you take on a third income source, the same logic applies: every additional source of income above your existing basic-rate usage is taxed at your marginal rate from the first pound
• Consider self-assessment voluntarily if you have complex income from multiple sources -- it gives you full visibility and control over your tax position rather than relying on PAYE estimates

The CalcHub Take-Home Pay Calculator allows you to enter up to two income sources and see the combined tax, NI, and take-home figures for 2026/27, which is a useful starting point before calling HMRC.