Taking on a second job is increasingly common — whether for extra income, a career change, or freelance work alongside an existing role.
But many people picking up additional employment are unaware of how a second job affects their 1257L tax code and, more importantly, what happens to their personal allowance as a result.
The 1257L tax code and a second job do not simply combine in the way you might expect.
Your personal allowance of £12,570 can only be allocated once across all your income — it cannot be doubled up.
This means that whilst your main employer may apply the 1257L tax code in the usual way, your second employer is likely to receive a different code altogether — often one that results in tax being deducted from the very first pound you earn in that role.
For anyone with a 1257L tax code and a second job, understanding how HMRC distributes your allowance — and what codes your second employer might receive — is essential for avoiding tax surprises.
This guide explains how the system works, which codes are commonly applied to second employment, what the financial impact may look like at different income levels, and what to do if something does not seem right.
Why the 1257L Tax Code Can Only Apply to One Job
The personal allowance — the amount of income you may earn each year before income tax applies — is a single annual entitlement.
For the 2025/26 tax year, that figure is £12,570, and it is this amount that the 1257L tax code reflects. The key point is that this allowance exists once per person, not once per employment.
When you have two jobs, HMRC typically assigns the full personal allowance to one of them — usually your primary or highest-earning employment.
That job receives the 1257L tax code, meaning your employer deducts tax only on the portion of your earnings that exceeds £12,570 over the course of the year.
Your second employment, however, has no remaining allowance to offset against. From HMRC’s perspective, your tax-free entitlement has already been used.
As a result, your second employer is instructed to deduct income tax from your earnings in that role without applying any personal allowance at all.
This is why the tax code on a second job tends to look very different from the 1257L code you see on your main payslip.
This approach is not a mistake or an error — it is how the PAYE system is designed to prevent individuals from receiving their tax-free allowance more than once.
Which Tax Code Does a Second Job Usually Receive?
The code applied to your second employment depends on your total earnings and how your income is distributed across both jobs.
There are three codes you are most likely to encounter in a second employment scenario.
BR (Basic Rate) is the most common code for second jobs. It means that all income from that employment is taxed at the basic rate of 20%, with no personal allowance applied.
If your combined earnings across both jobs keep you within the basic-rate band (below £50,270 for 2025/26), BR is likely the appropriate code for your second role.
D0 (Higher Rate) is applied when your total income from both employments is expected to put you into the higher-rate band.
It taxes all income from the second job at 40%, again with no personal allowance. If your main salary is already close to or above £50,270, HMRC may issue a D0 code to your second employer.
D1 (Additional Rate) taxes all second-job earnings at 45% and is used when total income is expected to exceed £125,140. This is less common but relevant for higher earners taking on additional paid work.
In some cases — particularly at the start of a new second employment — your second employer may apply an emergency code such as 1257L M1 or 0T until HMRC issues the correct code.
This can sometimes result in too little tax being deducted initially, which HMRC may then recover later in the tax year.
How the 1257L Tax Code and a Second Job Affect Your Take-Home Pay
The practical effect of having a BR or D0 code on a second job is that your effective tax rate on that income is higher than it might initially seem.
Every pound you earn in your second role is taxed from the outset, without any tax-free buffer.
Scenario A — Two jobs, both within the basic-rate band
Suppose your main job pays £22,000 per year and your second job pays £8,000.
- Your main employer holds the 1257L tax code and deducts tax on £9,430 (£22,000 minus the £12,570 personal allowance) at 20% — roughly £1,886 per year.
- Your second employer holds a BR code and deducts 20% on the full £8,000 — a further £1,600.
- Your combined tax liability is approximately £3,486, which matches what you would pay on a single income of £30,000 under the standard 1257L code.
In this scenario, having two jobs does not increase your overall tax bill — it simply splits the calculation across two payrolls.
The cash-flow experience can feel different: your second-job pay is reduced by 20% from day one, rather than having a tax-free portion each month.
Scenario B — Second job pushes income into the higher-rate band
Now suppose your main salary is £46,000 and your second job pays £10,000. Your main employer applies 1257L, meaning tax is deducted on £33,430 at 20% (£6,686 per year).
The remaining £4,270 of basic-rate band (from £46,000 to £50,270) is already used by the main job.
The additional £10,000 from the second job falls almost entirely into the higher-rate band.
HMRC may issue a D0 code to your second employer, meaning that income is taxed at 40% — producing approximately £4,000 in additional tax.
These are illustrative figures. Your actual position depends on both incomes, any allowable expenses, pension contributions, and other adjustments.
An income tax calculator can provide a more precise estimate for your specific situation.
Splitting the Personal Allowance Across Two Jobs
In most cases, HMRC allocates the full personal allowance to a single employment.
There is an alternative approach: requesting that HMRC split the personal allowance between your two employments, so that a portion of the £12,570 is reflected in the tax code for each job.
This can be useful if your two incomes are similar in size and you would rather have a portion of your monthly earnings tax-free across both payrolls, rather than all the relief concentrated in one.
For example, if you earn £15,000 from each job, HMRC could allocate £6,285 of personal allowance to each, resulting in a code of around 628L on each employment.
The overall tax position is the same either way — you are not paying more or less tax in total. The difference is purely in how and when that tax is collected.
Some people prefer the split approach because it improves cash flow month to month, whilst others find it easier to keep the standard 1257L on one job and a BR code on the other.
To request a split allocation, you would typically contact HMRC directly via your personal tax account or by telephone. HMRC would then issue revised coding notices to both employers.
Common Mistakes That Lead to Underpaid or Overpaid Tax
Having two jobs introduces more complexity into your tax position, and there are several common errors that can result in paying too much or too little tax.
Receiving 1257L on both jobs is probably the most financially significant mistake. If both employers hold a 1257L tax code simultaneously, you are effectively being given twice the personal allowance — meaning you are likely underpaying tax on one of your employments.
HMRC tends to catch this discrepancy during year-end reconciliation and may issue a demand to recover the underpaid amount, sometimes covering multiple tax years.
Using an emergency code for too long on the second job is another common issue. If you started the second role without providing a P45 from a previous employer, or without completing a starter checklist correctly, your second employer may have applied 1257L M1 or 0T on a non-cumulative basis.
This can result in inconsistent deductions — sometimes too much tax, sometimes too little — until HMRC issues the correct code.
Not accounting for the end of the second job can also cause problems. If you leave a second employment part-way through the tax year, HMRC may not immediately adjust the code on your main job to reflect the change in your total expected income.
You could end up overpaying or underpaying tax for the remainder of the year if the coding is not updated promptly.
What to Do When You Start a Second Job
When you take on additional employment, there are a few practical steps worth taking to ensure your tax codes are applied correctly from the outset.
If you are leaving a previous second job to start a new one, providing your new employer with a P45 from the role you are leaving allows them to set up your payroll correctly from day one.
Without a P45, your new employer is likely to place you on an emergency code initially.
If you are adding a second job on top of existing employment you are staying in, you will not have a P45 to provide.
In this situation, you may be asked to complete a starter checklist. The answers you give — particularly around whether you have other employment — help your new employer apply the most appropriate interim code until HMRC issues an official one.
It is also worth checking your personal tax account after your first or second payslip from the new role, to confirm that HMRC has the correct picture of your income from both employments.
If your coding notices do not reflect both jobs within a few pay periods, it may be worth contacting HMRC proactively to update your records.
Self-Employment Alongside a 1257L Tax Code
A growing number of people combine employed PAYE income with self-employed earnings — for example, working a salaried role whilst also running a small business or taking on freelance projects.
This situation differs from having two PAYE jobs, and the interaction with the 1257L tax code works differently.
Self-employed income is generally declared and taxed through Self Assessment rather than PAYE. Your employed income continues to use the 1257L tax code in the usual way.
If HMRC becomes aware of your self-employed income — either through your own notification or from data in your tax return — they may adjust your PAYE tax code to collect some or all of the tax owed on that income through your employment.
This process, known as coding out, reduces the number in your PAYE tax code to collect additional tax in-year.
For example, if HMRC estimates you owe £500 in tax on self-employed income, your code might be reduced from 1257L to 1207L.
This lowers your monthly take-home pay from your employed role to recover the expected liability gradually.
Whether HMRC codes out your self-employed tax or collects it through Self Assessment depends on the amount owed and your individual circumstances.
If you have recently started self-employment alongside your PAYE role, it is worth being aware that your 1257L code may be adjusted without a change in your employment situation.
1257L Tax Code and a Second Job — What You Need to Keep in Mind
The relationship between your 1257L tax code and a second job is governed by one straightforward principle: your personal allowance can only be used once.
Your main employment typically holds the standard 1257L code and benefits from the full £12,570 tax-free allowance.
Your second employment is generally issued a BR, D0, or D1 code depending on your combined income level, meaning tax is collected on every pound earned in that role.
Being aware of this distinction matters because errors — particularly having two employers both using the 1257L code — can lead to significant underpayments that HMRC may seek to recover.
Equally, an emergency code applied for longer than necessary on a second job can result in overpaid tax that takes time to reclaim.
Checking your coding notices when you start new employment, and reviewing your personal tax account periodically, tends to be the most reliable way to stay on top of your position.
For more detail on how tax codes are assigned across different employment situations, see the tax codes guide on taxrebateservices.co.uk.
Key Takeaways
- The 1257L tax code reflects the standard personal allowance of £12,570, which can only be allocated to one employment — it cannot apply to both jobs simultaneously.
- Your second employer is typically issued a BR code (20% tax on all earnings), a D0 code (40%), or a D1 code (45%), depending on your total income from both roles.
- Having the 1257L code active on two employments at the same time is a common error that may result in underpaid tax, which HMRC could seek to recover later.
- It is possible to ask HMRC to split the personal allowance between both jobs, which may improve monthly cash flow without changing your overall tax liability.
- Self-employed income alongside PAYE employment can also affect your tax code, as HMRC may reduce the number in your 1257L code to collect estimated tax on self-employed earnings through your payroll.
- Checking your personal tax account after starting a second job, and confirming that coding notices reflect both employments, is the most straightforward way to avoid errors.
1257L and Second Job FAQs
Q1: Can I have the 1257L tax code on both my jobs?
Generally, the 1257L tax code applies to only one employment — your main or highest-paying job. Your personal allowance of £12,570 can only be allocated once, so your second job is typically assigned a different code such as BR, D0, or D1. If both employers are using 1257L simultaneously, you may be receiving your personal allowance twice, which could result in underpaid tax that HMRC seeks to recover later.
Q2: What tax code will my second job have?
The most common code for a second job is BR, which taxes all earnings at the basic rate of 20% with no personal allowance. If your combined income from both jobs is likely to put you into the higher-rate band (above £50,270 for 2025/26), your second employer may receive a D0 code instead, meaning all second-job income is taxed at 40%. The specific code depends on your total expected earnings across both roles.
Q3: Why is 20% tax being deducted from every pound of my second job earnings?
This is because a BR code has been applied to your second employment. Since your personal allowance of £12,570 is already being used by your main job, there is no remaining allowance to offset against your second income. As a result, every pound you earn in the second role is taxable from the outset. This is the normal arrangement under PAYE when someone holds two concurrent employments.
Q4: Can I split my personal allowance between two jobs?
Yes, it is possible to ask HMRC to divide your personal allowance between both employments, so that a portion is reflected in the tax code for each job. This does not change your total tax liability — the same overall amount is owed — but it can improve your monthly take-home pay from both roles, as a portion of earnings from each becomes tax-free. You would need to contact HMRC to request this arrangement.
Q5: What happens to my 1257L tax code if I leave my second job?
When you leave a second employment, your overall expected income for the tax year changes. HMRC may need to update the coding on your main job to reflect the fact that your second income has ended. If the coding is not updated promptly, you could pay too much or too little tax for the remainder of the year. It is worth checking your personal tax account after leaving a second role to confirm your main 1257L code has not been adjusted incorrectly.
