Written by the TaxTune Editorial Team·Reviewed by our qualified accountants·Updated June 2026

How your personal allowance is split

Everyone has a tax free personal allowance of £12,570 for 2026/27. When you have one job, the whole allowance is usually applied to it through your tax code, so the first slice of your pay is tax free and the rest is taxed in the normal bands.

When you take a second job, HMRC does not split the allowance across both by default. Instead it normally leaves the full allowance with your main job and taxes your second job differently. This is the source of most of the confusion, because your second job then has no tax free amount of its own. Understanding how your tax code is built is the key to making sense of it, and our guide to how tax codes work explains the letters and numbers in detail.

The logic is reasonable. Your allowance can only be used once, so HMRC parks it with one job and taxes the other on the assumption that the allowance is already spent.

The BR tax code explained

A second job is usually given the tax code BR, which stands for basic rate. A BR code means every pound from that job is taxed at the 20% basic rate, with no personal allowance applied. This is not a penalty. It simply reflects that your tax free allowance is already being used by your main job.

For many people with two jobs, BR produces roughly the right result. If your main job uses up your personal allowance and your combined income stays within the basic rate band, taxing the second job at a flat 20% is broadly correct. The system runs into trouble when your income does not match those assumptions, which is where over and underpayments come from.

You may also see codes such as D0, which taxes the second job at the higher rate, used where your income is high enough that the second job should be taxed at 40%. The code chosen depends on what HMRC expects your total income to be.

When you overpay or underpay

The flat BR code is an estimate, and estimates can be wrong when your circumstances do not fit the standard pattern. There are two main ways this goes astray.

  • You can overpay if your main job does not use all of your personal allowance. For example, if your main job pays less than £12,570, part of your allowance is wasted, yet your second job is still taxed at 20% from the first pound. You have paid tax you did not need to.
  • You can underpay if your combined income pushes you into the higher rate, but your second job is only taxed at the basic rate of 20%. The extra tax due on income above £50,270 is not collected through a simple BR code, leaving a shortfall.

Because a second job is usually taxed with a BR code while the personal allowance sits with the main job, your tax can end up too high or too low whenever your income changes during the year. The bands that decide all this are set out in our guide to the income tax rates and bands.

A worked example

Worked example

James has two part time jobs

James earns £10,000 a year from his main job and £8,000 from a second job, giving total income of £18,000 in 2026/27. His main job uses a standard code, so its £10,000 is covered by his personal allowance and pays no tax. His second job is given a BR code, so all £8,000 from it is taxed at 20%, producing £1,600 of tax. Yet James's total income of £18,000 is only £5,430 above his £12,570 personal allowance, so the correct tax should be 20% of £5,430, which is £1,086. The BR code has caused James to overpay by £514 across the year because part of his personal allowance sat unused in his lower paid main job.

James can fix this by asking HMRC to move part of his personal allowance onto his second job, so both jobs share the tax free amount in line with what each actually pays. Once the codes are adjusted, his total tax falls to the correct figure.

Common mistakes

The most common misunderstanding is believing a second job is taxed at a special high rate to punish you for having two. It is not. BR is simply the basic rate with no allowance attached, because the allowance is already in use elsewhere.

People also assume the codes will always be correct and never check them, which is how overpayments go unnoticed for years. Others forget that extra income outside employment, such as freelance work, is not covered by a BR code at all and must be reported separately. You must tell HMRC about untaxed income. Some people swap which job is their main one without telling HMRC, leaving the allowance attached to the wrong job, and a few assume HMRC will automatically refund any overpayment without them needing to query the codes.

What you should do

Start by checking the tax code on each payslip. If your main job pays less than your personal allowance, contact HMRC and ask for the unused part of your allowance to be applied to your second job. If your combined income takes you into the higher rate, be aware that a BR code may leave you underpaid, and a Self Assessment return may be needed to settle the difference. Our guide to how Self Assessment works explains when filing is required.

If you would rather not work through the codes yourself, we can review both jobs, check that your allowance is allocated efficiently, and deal with HMRC to correct any errors and reclaim overpaid tax. To get started, start your quote.

In short

A clear explanation of how a second job is taxed, why the BR code is used, when you over or underpay, and how to put your tax code right.

Frequently asked questions

Is a second job taxed more than a first job?
No. A second job is not taxed at a higher rate as a penalty. It is usually given a BR code, which taxes it at the basic rate of 20% with no personal allowance, because your allowance is already applied to your main job. The total tax across both jobs should reflect your overall income.
What does a BR tax code mean?
BR stands for basic rate. A BR code means all the income from that job is taxed at 20% with no tax free personal allowance applied. It is typically used on a second job because the personal allowance is already being used by your main job, so there is no allowance left to apply to the second.
Why have I overpaid tax on my second job?
Overpayments usually happen when your main job does not use all of your personal allowance. If your main job pays less than £12,570, part of your allowance is wasted while your second job is still taxed from the first pound. You can ask HMRC to move part of your allowance to the second job to fix this.
Could I underpay tax with two jobs?
Yes. If your combined income from both jobs pushes you into the higher rate, but your second job is only taxed at the basic rate through a BR code, the extra tax on income above £50,270 may not be collected. This can leave a shortfall that you may need to settle, sometimes through Self Assessment.
How do I get my tax code corrected?
Contact HMRC and explain how your income is split between your jobs. They can adjust the codes so your personal allowance is allocated in the most efficient way. Checking the code on each payslip is the first step. If you would prefer, an accountant can review your codes and deal with HMRC on your behalf.
Do I need to file a tax return for a second job?
Not usually, if both jobs are taxed under PAYE, as the tax is collected through your codes. However, you may need to file if your combined income takes you into the higher rate and tax is owed, or if you also have untaxed income such as freelance work. You must tell HMRC about untaxed income.