9 Reasons You Might Be Due A Tax Refund​

If you’re wondering whether you might be owed money back from HMRC, you’re not alone. 

Every year, millions of people overpay tax without realising it. Sometimes it’s a simple tax code error. Sometimes it’s because your circumstances changed. Sometimes it’s because HMRC didn’t have the full picture. 

If any of the situations below sound familiar, there’s a good chance you could be due a tax refund. 

1. You’re on the wrong tax code 

Tax codes are supposed to reflect your personal allowance and any adjustments to your tax position. When they’re right, everything runs smoothly. 

When tax codes are wrong, you can quietly overpay for months or even years. 

Tax codes can be incorrect if: 

• You changed jobs
• You have more than one job
• You stopped receiving a benefit in kind
• HMRC used estimated income figures 

If HMRC later corrects your code and confirms an overpayment, you may receive a refund through PAYE or a P800 calculation. 

You can learn more in our guide to tax codes explained.  

2. You changed jobs during the tax year 

Changing jobs can easily cause overpayments. 

Common triggers include: 

• Starting a new job on an emergency tax code
• Not giving your new employer your P45
• Overlapping payroll periods
• Leaving work mid-year 

If you left a job and were out of work for part of the tax year, you may have paid too much tax because your personal allowance wasn’t fully used. 

Our P45 guide explains how this works.  

3. You paid emergency tax 

Emergency tax is often applied when HMRC or your employer doesn’t yet have your full income details. 

This can happen if: 

• You start a new job
• You move from employment to pension
• You receive a lump sum payment 

Emergency tax codes codes often mean you pay more tax than necessary initially. Once your details are corrected, you may be due money back.  

What is an emergency tax code?

4. You paid for work expenses yourself 

If you paid for things you needed to do your job and your employer didn’t reimburse you, you may be entitled to tax relief. 

Common claims include: 

• Uniform and specialist clothing costs 
• Mileage for temporary workplaces 
• Working from home expenses 
• Tools and professional subscriptions 

Many employees never claim these expenses. Over four years, that can add up significantly.  

5. You’re self-employed and overpaid on account 

If you’re registered for Self Assessment tax returns, you may make Payments on Account based on previous income. 

If your income later dropped, you may have: 

• Overpaid in advance
• Paid more than your final liability 

When HMRC recalculates your position, you could be due a repayment.  

6. You received a pension lump sum 

Pension lump sums are often taxed using an emergency code initially. It’s possible to end up paying too much tax on your private pension, but you can still get back what you’re owed. 

This can result in overpayment, especially if: 

• You withdrew part of your pension pot
• It was your first withdrawal
• You have little other income 

Depending on your situation, you may need to submit forms such as P53 or P50Z, or wait for a P800 calculation. 

How much should you have in your pension pot?  

7. You received redundancy pay 

Redundancy payments are partly tax-free, but mistakes can happen. 

If too much tax was deducted from: 

• Your final salary
• A lump sum
• A holiday payout 

you may be able to reclaim it. 

We explain this in more detail in our our guide: Tax refunds & redundancy  

8. You earned savings or PPI interest 

Savings interest may be taxed incorrectly if: 

• Your bank applied tax when you were under your Personal Savings Allowance
• You qualify for the starting rate for savings
• Your income fell below the Personal Allowance 

In some cases, you can reclaim using form R40 if you are not in Self Assessment. 

Our guide to Trading allowance explained also covers small income thresholds.  

9. You had overseas income or worked abroad 

International income can create overpayments if: 

• Double taxation wasn’t applied correctly
• HMRC didn’t account for overseas residency
• Foreign tax was paid but not offset 

The UK has double taxation agreements with many countries, but errors still happen if information is incomplete. 

If you’re unsure how your residency affects your tax, professional advice can prevent you from leaving money unclaimed. Here’s our guide on Paying tax while working overseas.  

How far back can you claim? 

You can usually claim a tax refund going back four tax years. After that, the window closes. That means it’s worth reviewing your situation even if the issue wasn’t recent.  

How do you check if you’re owed a tax refund? 

You can: 

• Review your tax code
• Log into your Personal Tax Account
• Check for a P800 letter
• Review past Self Assessment returns 

Or you can use our free Tax rebate calculator to get an instant estimate. 

It takes less than a minute and there’s no obligation. 

Why do so many refunds go unclaimed? 

Most overpayments happen because: 

• People assume PAYE is always correct
• Circumstances change but records don’t
• Small claims are ignored
• The process feels complicated 

HMRC isn’t trying to keep your money. But it relies on accurate information. 

If something was missed, it’s usually up to you to correct it.  

You might be owed more than you think 

Across four tax years, small annual overpayments can add up.

Uniform cleaning costs. Mileage claims. Incorrect codes. Emergency tax. A short gap between jobs. Individually they may seem minor. Combined, they can make a meaningful difference. 

If any of these reasons sound familiar, it’s worth checking. 

Start with our tax rebate calculator and see where you stand.