Does RIFT Refunds Change your Tax Code?

In short, no. RIFT cannot directly change your tax code. HMRC sets and issues PAYE tax codes. Your employer or pension provider then uses the code HMRC gives them to work out how much Income Tax to deduct.

If RIFT is authorised to act for you, we can give HMRC relevant information or raise a query about your PAYE code, but HMRC decides whether your tax code changes and issues the new code.

However, once you claim a tax refund, it's possible that it may trigger a tax code change. Understanding your tax code is a big part of getting the best from your financial situation. Even so, it’s still something that confused a lot of people. When your tax code changes, it means your circumstances have made a difference to the tax you owe—and it’s not necessarily bad news. That’s why RIFT always takes such great care to make sure your code’s correct.

What does a tax code do?

Your tax code tells an employer or pension provider how HMRC wants your Income Tax calculated.

For many people receiving the standard Personal Allowance in 2026/27, the familiar code is 1257L.

The number in a normal tax code usually gives an indication of the tax-free amount HMRC has allocated to that source of income. For example, 1257 generally corresponds to £12,570.

There are exceptions, including K tax codes and codes that do not contain a number.

The letters give additional information about how the code operates.

Scottish taxpayers may see an S prefix and Welsh taxpayers may see a C prefix.

Why might HMRC change my tax code?

A code can change when the information HMRC holds about you changes.

That can include starting or leaving a job, having more than one job or pension, receiving a taxable workplace benefit, getting tax relief for employment expenses, using Marriage Allowance or HMRC collecting tax that was underpaid in an earlier period.

A change in your code isn’t automatically evidence that anything has gone wrong.

Can a tax refund affect my tax code?

Sometimes.

If you get tax relief for qualifying employment expenses for the current tax year, HMRC will usually deal with that relief by adjusting your tax code so that less tax is deducted from your pay.

For previous tax years, HMRC may adjust a code or make a refund, depending on the circumstances.

This is one reason a tax code can change after HMRC processes employment expenses.

Can HMRC carry employment expenses into a future tax code?

Yes, some employment-expense figures can be included in later tax codes.

That can be helpful when the expense continues, but the figure needs to reflect your actual circumstances.

HMRC says that if you make an estimated expense claim and your actual expenses turn out to be different, you must tell them.

For someone whose qualifying travel or other costs vary from year to year, that is an important point.

Can I have more than one tax code?

Yes.

If you have more than one PAYE job or pension, each employment or pension will usually have its own tax code.

You still only have one Personal Allowance for the tax year.

HMRC may allocate that allowance to one source of income or divide it between sources, depending on your circumstances.

A second job might therefore have a code such as BR, D0 or D1, but this depends on your total income and tax position.

Does Marriage Allowance change tax codes?

Usually.

If Marriage Allowance is being transferred, HMRC says the person receiving it will normally have a tax code ending in M.

The person transferring the allowance will normally have a tax code ending in N.

The numbers before the letters can vary, so Marriage Allowance does not automatically mean everyone receiving it has exactly the same numeric tax code.

Read more about Marriage Allowance here

What are emergency tax codes?

For 2026/27, emergency tax codes include 1257L W1, 1257L M1 and 1257L X.

They can be used where an employer doesn’t yet have enough information to operate your normal cumulative tax position.

If you’ve just started a new job, give your employer your P45 or complete HMRC’s starter checklist if you don’t have one.

What happens if my tax code is wrong?

You may pay too much or too little Income Tax.

If you pay too much, HMRC may repay the difference.

If you pay too little, HMRC may need to collect the amount you owe.

A wrong PAYE tax code does not automatically create a fine or penalty.

The priority is to make sure HMRC has accurate information about your income and circumstances.

How do I check or correct my tax code?

You can check your tax code through HMRC’s online Income Tax service or HMRC app.

If information about your income or employment is wrong, you can update it directly.

HMRC says that once it has changed a code, it will normally tell you and your employer the new code within 15 working days. It should then appear on a subsequent payslip.

If an authorised tax agent is acting for you, the agent can also raise a PAYE coding query with HMRC where appropriate.

So, can RIFT change my tax code?

No.

RIFT can help explain the information behind a tax-code issue and, where authorised, communicate relevant information to HMRC.

HMRC remains responsible for deciding and issuing your tax code.

That distinction matters because nobody outside HMRC can simply choose a new PAYE code for you.