WHAT IS THE M1 TAX CODE?

The M1 Tax Code is an emergency tax code used by HMRC when it does not have enough information to calculate your Income Tax correctly. If you’ve recently started a new job, changed employers, or begun receiving a pension, you may notice the M1 Tax Code on your pay slip. It tells your employer to calculate tax on a Month 1 basis, meaning each month’s pay is taxed separately instead of considering your earnings and tax paid earlier in the tax year.

Many people worry when they see the M1 Tax Code, but it is usually temporary. It does not necessarily mean you owe HMRC money or that you have been taxed incorrectly. Instead, it allows HMRC to collect tax while waiting for updated employment details, such as your P45 or payroll information. Once the correct information is received, your tax code is normally updated automatically.

DOES THE M1 TAX CODE MEAN YOU WILL PAY MORE TAX?

One of the biggest concerns about the M1 Tax Code is whether it leads to higher tax payments. The answer is that it can, but usually only temporarily.

Since the emergency tax code calculates tax on a Month 1 basis, it does not account for any unused Personal Allowance from previous months. If you had little or no income earlier in the tax year, you may temporarily pay more tax than necessary.

Fortunately, HMRC reviews your tax records regularly. If you have overpaid tax because of your current tax code, the excess amount is generally refunded once your correct tax code is applied.

WHY HAS HMRC PUT ME ON AN EMERGENCY TAX CODE?

Yes. The HMRC’s temporary tax code is commonly known as an emergency tax code because HMRC uses it when it does not yet have enough information to calculate your Income Tax on a cumulative basis. If you’ve recently started a new job, changed employers, or begun receiving a pension, you may temporarily be placed on the M1 tax code.

Although the M1 tax code is an emergency measure, it does not mean you have done anything wrong. It simply allows HMRC to collect tax while your employment records are updated. Once the correct information is received, HMRC usually replaces the M1 emergency tax code with your normal tax code.

WHY HAS HMRC GIVEN ME THE M1 TAX CODE?

Many taxpayers ask, “Why have I been given the M1 tax code?”

HMRC may issue your current tax code for several reasons, including:

• Starting a new job without providing a P45.
• Delays in processing your employment details.
• Receiving your first pension payment.
• Working more than one job.
• Returning to work after unemployment.
• Missing or outdated information on your HMRC record.

In most cases, the M1 tax code is temporary and will be corrected once HMRC receives updated information from your employer or pension provider.

DOES THE M1 TAX CODE MEAN YOU WILL PAY MORE TAX?

One of the biggest concerns people have about the emergency PAYE code is whether it results in paying too much tax.

Because the M1 tax code ignores unused Personal Allowance from earlier months in the tax year, many employees temporarily pay more Income Tax than they actually owe. This overpayment usually happens because each month’s salary is taxed independently instead of using a cumulative calculation.

The good news is that any tax overpaid while on the emergency tax code is normally refunded once HMRC updates your records.

HOW LONG WILL YOU STAY ON YOUR CURRENT TAX CODE?

The M1 tax code is not intended to be permanent.

Most taxpayers remain on the M1 emergency tax code for only a short period while HMRC processes information received from their employer or pension provider.

The time can vary depending on:

• When your employer submits payroll information.
• Whether HMRC has received your P45.
• Any delays in updating PAYE records.
• Changes to your employment status.

Once HMRC has enough information, your tax code is normally changed automatically.

HOW CAN YOU REMOVE THE M1 TAX CODE?

If you believe the M1 tax code is incorrect, you should contact HMRC as soon as possible.

You can usually resolve the issue by:

• Providing your P45 to your employer.
• Completing a Starter Checklist accurately.
• Updating your employment details through your HMRC Personal Tax Account.
• Contacting HMRC directly by telephone.

Taking action quickly can help reduce any temporary tax overpayments caused by this tax code.

CAN YOU CLAIM A REFUND IF YOU OVERPAY TAX ON THE M1 TAX CODE?

Yes.

If you paid too much tax while on the non-cumulative tax code, HMRC will normally refund the excess.

Depending on your circumstances, the refund may be made:

• Through your employer’s payroll.
• Via a P800 tax calculation after the tax year ends.
• Directly into your bank account through your Personal Tax Account.

Checking your tax code regularly can help you identify problems before significant overpayments occur.

WHAT IS THE DIFFERENCE BETWEEN THE M1 TAX CODE AND A NORMAL TAX CODE?

The main difference is how tax is calculated.

A normal cumulative tax code takes into account:

• Previous earnings.
• Previous tax paid.
• Unused Personal Allowance.

The M1 tax code, however, ignores previous months and treats every payroll period as though it were the first month of the tax year.

This difference is why many employees temporarily pay more tax under HMRC’s temporary tax code.

HOW TO CHECK IF YOU ARE ON THE M1 TAX CODE

You can easily check whether you’re on the M1 tax code.

Look for your tax code on:

• Your pay slip.
• Your P60.
• Your HMRC Personal Tax Account.
• Your PAYE Coding Notice.

If your code includes “M1”, such as 1257L M1, your Income Tax is currently being calculated on a Month 1 basis.

COMMON MISUNDERSTANDINGS ABOUT THE M1 TAX CODE

There are several myths about the emergency PAYE code.

Some people believe:

• The M1 tax code is a penalty from HMRC.
• It means you owe tax.
• It is a permanent tax code.
• It cannot be changed.
• You lose your Personal Allowance completely.

None of these are true.

This tax code is simply a temporary emergency tax code that HMRC uses until your correct tax information becomes available.

KEY FACTS ABOUT THE M1 TAX CODE

If you’re trying to understand the M1 tax code, remember these important points:

• The M1 tax code is an emergency tax code.
• It calculates tax on a Month 1 (non-cumulative) basis.
• It often causes temporary Income Tax overpayments.
• Most taxpayers are moved off  your current tax code once HMRC receives updated information.
• Any overpaid tax is normally refunded automatically.

Understanding how non-cumulative tax code works can help you identify overpayments quickly and ensure you’re paying the correct amount of Income Tax.