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An X at the end of your tax code means you are on an emergency, non-cumulative tax code. Your tax is calculated using only the income you receive in the current pay period, without taking account of your pay and tax from earlier in the tax year. |
X normally appears at the end of a complete tax code, rather than being used as a tax code on its own.
For example, your payslip could show:
The main part of the code tells your employer how much tax-free income and which tax rules to apply. The X tells payroll to calculate your tax using the current pay period only.
This is known as a non-cumulative basis.
Under a normal cumulative tax code, your employer considers your total taxable pay and the Income Tax you have paid since the beginning of the tax year.
Under an X code, earlier pay and tax are not included in the calculation. Your employer treats the current payment as a separate period.
No. An X tax code does not mean all your income is taxed at the basic rate.
The amount of tax deducted depends on:
For example, 1257L X normally provides a proportion of the standard Personal Allowance for the current pay period.
By comparison, 0T X provides no Personal Allowance for that period. Income may then be taxed across the relevant basic, higher and additional-rate bands, depending on how much is paid.
The X changes how the calculation is applied. It does not set one fixed tax rate.
When an X tax code is used, payroll does not look back at your income and tax from earlier in the tax year.
Instead, you receive the proportion of your tax-free allowance and tax bands available for that particular week or month.
This can prevent a large adjustment being made through one payslip while HMRC confirms your information. However, it can also mean you pay too much or too little tax overall.
You could pay too much tax if:
You could pay too little tax if:
An X tax code is not necessarily wrong. However, you should check that the full code and the information HMRC holds about you are accurate.
You might be assigned the X tax code if HMRC doesn’t yet have all the information needed for your full tax code. It’s often applied in situations like when you start a new job, switch from self-employment to employment or begin receiving company benefits or a State Pension.
Similar emergency codes, like W1 (Week 1) or M1 (Month 1), also temporarily apply basic rate tax without adjustments, so keeping your details accurate can help avoid these, too.
While these codes are usually updated once HMRC has all your information, spotting them on your payslip is a good reminder to double-check that your tax details are up-to-date to avoid any overpayment or underpayment issues.
X, W1 and M1 are all emergency tax-code markers. They all mean tax is calculated using the current pay period rather than cumulatively.
The difference normally relates to how you are paid:
In each case, the full tax code still matters.
For example, 1257L M1 and 1257L X both include a proportion of the standard Personal Allowance for the current period. Neither code simply taxes all income at the basic rate.
An X tax code is often temporary when it is used because you have started a new job and information is missing.
HMRC will normally update your tax code after receiving the necessary details from you and your current and previous employers. This can take up to 35 days from the date you start a new job.
However, an emergency code may sometimes remain in place until the end of the tax year. This can happen when it is being used to account for something such as a new company benefit or the State Pension.
You should therefore check the reason for your code rather than assuming it will automatically change after your next payday.
1) Check your payslip
Look for the X tax code on your payslip. This code indicates HMRC needs more information to finalise your tax code.
2) Contact your employer
Ensure your employer has the correct details about your previous jobs, tax information and any changes in your work status.
3) Update your details with HMRC
Use your Personal Tax Account online to update any recent changes, such as new jobs, income sources or benefits.
4) Follow up for updates
Keep an eye on your payslip and tax code notices. Once HMRC receives the necessary information, they should assign the correct tax code, adjusting any deductions.
You might need to change your tax code if you start a new job, receive additional income, or if your personal allowance changes. It’s good to keep an eye on any tax code changes. If it’s wrong, you might be taxed too much or too little.
If you have just started a new job, HMRC advises allowing up to 35 days for your employment information and tax code to be updated.
If more than 35 days have passed and the code still appears to be wrong, check your tax details online or contact HMRC.
Once HMRC issues a new code, your employer should normally use it:
Continue checking your payslips until the new code has been applied.
If you’ve been overtaxed because of the X tax code, you may be eligible for a tax rebate. Once HMRC has assigned your correct tax code, any overpaid tax is usually refunded automatically. However, this doesn’t always happen promptly, and that’s where a helping hand can make a difference.
At RIFT, we specialise in making tax refunds simple and hassle-free. We’ll review your situation, help ensure all your tax details are accurate, and assist with any paperwork needed to claim your rebate. With us on your side, getting back what you're owed is easy and stress-free.
To avoid being assigned the X tax code, it’s essential to keep your tax records up-to-date. Here’s how:
When starting a new job, ensure your employer has all your tax details, including your P45 or information about any additional income.
Use your Personal Tax Account to inform HMRC of any changes in employment status, income sources, or benefits.
Regularly check your tax code on your payslip to spot any changes early.
Want help keeping everything in order? Get in contact with us. We specialise in tax refunds and can help ensure your tax code and records are accurate. Our easy-to-use tax rebate calculator will quickly show you if you’re owed money. If you've been overtaxed, we’ll help you get back what you’re owed, saving you from unwanted surprises.
No. The X does not determine whether you receive a Personal Allowance.
The numbers and letters before the X show the allowance applied. For example, 1257L X normally includes a proportion of the standard Personal Allowance, while 0T X does not.
Yes. HMRC classifies a code ending in X as an emergency tax code. It means the code is operated on a non-cumulative basis.
No. Tax may be deducted at different rates depending on your full code, income level and where in the UK you live.
It may be replaced automatically once HMRC receives the information it needs, particularly after you start a new job. However, you should check your HMRC account if the code appears incorrect or remains in place after 35 days.
Your employer can submit correct payroll information and apply a new code received from HMRC. It cannot normally decide to remove the X without the appropriate HMRC instruction.
Not always. A refund may be made through your pay after HMRC issues a corrected cumulative code. In other cases, HMRC may need more information or may review your position after the tax year ends.
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