Rapid Refund
Jump the queue, get 50% paid upfront
Average Claim £3,000
We'll tell you straight away what you're owed
Free to enquire
It's free to find out if you have a claim
No Hidden Costs
All aftercare is included
Last reviewed July 2026
| Quick answer: |
If you’ve got a K tax code for your job, it means you’ve got some income factored into it that isn’t being taxed any other way, and it’s over your Personal Allowance threshold. For example:
|
Most tax codes give your employer an amount of income that you can receive before Income Tax is deducted. The standard Personal Allowance for the 2026/27 tax year is £12,570, usually represented by the tax code 1257L.
A K code works differently. It appears when the amounts being deducted from your Personal Allowance are greater than the allowance available.
Your employer or pension provider is then told to add a notional amount to your taxable pay before calculating Income Tax. You do not actually receive this extra income. It is used for the tax calculation.
Let’s say you qualify for a standard Personal Allowance of £12,570, but you have some unpaid tax from a previous year and/or some tax to pay for the benefits you’re getting. Normally, on a standard L tax code, you’d simply have your tax-free Personal Allowance reduced to account for the extra tax you owe. However, if you owe enough this way to use up your entire Personal Allowance, you’ll be given a K tax code instead for the extra.
For example, suppose HMRC decides you owe tax on £15,000 of income or benefits that you aren’t already being taxed on some other way. You might be given a tax code of K243. This tells your employer to count your income as if it were £2,430 higher (the amount over your £12,570 Personal Allowance) when calculating how much tax to take out of it. It’s like having a negative Personal Allowance! It sounds nasty, but there are rules to give you a little protection. Whatever tax you owe, you can’t have more than half of your pre-tax pay taken out because of a K tax code.
HMRC may issue a K tax code when you:
A K code does not confirm that HMRC’s figures are correct. It shows how HMRC has decided the tax should be collected based on the information it currently holds.
A K tax code is not necessarily a sign that something has gone wrong. It may be the correct way for HMRC to collect tax on benefits, pension income or a previous underpayment.
It does mean that more of your wages or pension will be treated as taxable. You may therefore see a noticeable reduction in your take-home pay.
The important question is whether the information behind the code is accurate.
Check the code promptly if:
Most of the time, HMRC will alter your tax code for you as your circumstances change. However, there are times when you might end up on the wrong tax code – and when that happens you need to get it fixed fast. It’s your responsibility to get the problem sorted, and things can get very tricky if you don’t.
If you think your tax code’s wrong, you need to contact HMRC to make sure they have the information they need to put it right. If you’re claiming a tax rebate with RIFT, of course, we’ll check your tax code for you as part of the service. If you’re ever given the wrong code, we’ll get it corrected for you.
Find out more about how to change your tax code
Being on the wrong tax code can easily leave you paying the wrong amount of Income Tax on your earnings. For example, this can happen when:
Any of these situations can mean you’re paying too much Income Tax and might be able to claim a tax refund. Get in touch with RIFT to find out more about tax rebates, and to see how the UK’s leading experts can get back everything you’re owed.
K means the income, benefits or other deductions HMRC needs to account for are greater than your available tax-free Personal Allowance. An amount is added to your taxable pay so the tax can be collected through PAYE.
It can mean HMRC is collecting tax owed from an earlier year. K codes are also used for untaxed State Pension, taxable benefits, company benefits and savings interest, so a previous tax debt is only one possible reason.
K500 means approximately £5,000 is added to your taxable income across the tax year before Income Tax is calculated. It does not mean that your tax bill is £500 or £5,000.
The code alone cannot give you the final tax amount. Your tax depends on your earnings, tax band, location, other income and the figures already processed through PAYE.
Your employer or pension provider cannot deduct more than 50% of your pre-tax wages or pension when applying a K code. This is a maximum limit rather than the standard amount that will be taken.
Only HMRC can issue or change the tax code. Your employer or pension provider applies the code HMRC sends them.
HMRC says it will normally issue the updated code to you and your employer within 15 working days. Monthly employees should usually see it on their next or following payslip, while weekly employees should usually see it by their third payslip.
HMRC may repay an overpayment through your wages or after reviewing the tax year, depending on the circumstances. You may need to provide information or make a refund claim. Correcting the code and receiving a refund are separate steps, so check both.
At the heart of RIFT is a friendly, close-knit team. Each team member is here not only because they're incredibly talented - but because they love what they do and believe in helping our customers.
They're trained specifically in UK tax legislation and are ATT and FCCA qualified so you're in safe hands. Each of our customers are assigned a personal tax assistant too. Over the last 25 years, we have found that this continuity reduces duplication and improves accuracy.
The answer lies in experience, compliance and accountability. We have specialised exclusively in tax refunds since 1999. Over that time, we have reclaimed more than £400 million in overpaid tax for UK workers across travel, Construction Industry Scheme (CIS) and Armed Forces claims. We believe informed decisions build trust.
Of course you do! Get a grip on your cash with our free money saving tips, guides and videos sent straight to your inbox. What have you got to lose?
An M1 tax code is a bit like an emergency tax code. It should only be temporary until HMRC has enough information to issue the right code.
If you're on an NT tax code, you're in a pretty unusual position in that you're aren't paying income tax on your earnings from this job.
If you've got this tax code, you're in good company. This is the basic code that most people paying through the PAYE system will have.
