July 2024

Reviewed by Helen Lambkin, Assistant Operations Manager at RIFT Tax Refunds

Your tax code is a combination of numbers and letters that helps your employer know how to tax your earnings. You’ll have one for each job you have and it’s important to keep track of them. The last thing you want is to be over or underpaying tax due to the wrong tax code. 

Let’s take a look at the ins and outs of what the 1383M tax code means and how it might affect your tax-free personal allowance.

What does a tax code of 1383M mean?

In the UK, everyone receives a standard personal allowance. This is the amount you can earn before you have to start paying income tax. You get the tax code 1383M if you receive a transfer of 10% of your partner's personal allowance under the Marriage Allowance scheme. 

With Marriage Allowance, if you earn less than the standard personal allowance, your partner can transfer 10% of their personal allowance to you. It entitles you to a higher tax-free personal allowance, meaning you can earn more money before you have to start paying tax.

What does the M mean in my tax code?

The letters in your tax code indicate your specific situation and how it affects your tax-free personal allowance. Understanding these letters fully will help you to figure out whether you’re paying the right amount of tax. The standard tax code is 1257. 

The letter 'M' in your tax code means you’ve received 10% of your partner's personal allowance through the Marriage Allowance scheme. This transfer increases your tax-free income, reducing the amount of tax you need to pay.

Example of PAYE on tax code 1383M

With a 1383M tax code, your personal allowance is £13,830. This includes the standard personal allowance of £12,570, plus 10% of your partner's allowance – £1,260. 

Let’s say you earn £20,000 a year. Only £6,170 is taxable (£20,000 - £13,830), reducing the amount of income tax you pay. 

1383M is a cumulative tax code. If you return to work after a break or start working partway through the tax year, your tax-free personal allowance will have been building up. As a result, you could see yourself paying less tax for a little while.

Could you be due a tax refund?

If you think you’ve been paying the wrong amount of tax,  you can use the 'Check your Income Tax online' service available at HMRC's website. 

Helen Lambkin, Assistant Operations Manager at RIFT says:

If HMRC calculates that you’ve overpaid tax, they will issue you a P800 and you will automatically receive that cash back. However, if you are paying for work related expenses such as

  • Travel
  • Food
  • Accommodation
  • Laundry
  • Tools, equipment and PPC
  • Training expenses
  • Professional subscriptions, unions or licence fees 

You need to tell HMRC about this, they won’t know about it otherwise. That’s how thousands of pounds in overpaid tax goes unclaimed each year. RIFT can help with this. You can use our handy tax rebate calculator for an estimate of how much you could be owed back from HMRC.

Start your HMRC tax rebate claim today, and let’s get your money back.