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Understand your Simple Assessment tax bill

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Check your Simple Assessment tax bill

You should check the figures used in your Simple Assessment tax bill to make sure they are correct before paying. This will help make sure you pay the right amount of tax.

Your Simple Assessment will show:

  • your taxable income (for example, income from pay, pensions or state benefits)
  • any Income Tax you’ve already paid
  • the amount of tax you owe
  • a 14-character payment reference number (starting with X)

You’ll find a detailed breakdown of the calculation in the letter.

Some things such as receiving Marriage Allowance or tax you owe from a previous year may not appear as separate entries on your Simple Assessment. Instead, these amounts will usually be included in the total shown in the adjustments section of your Simple Assessment.

How to check your tax calculations

If you’re not sure the figures are correct, check the amounts in your Simple Assessment match those in your records, for example on:

  • your P60 or P45
  • bank statements
  • letters from the Department for Work and Pensions (DWP) or Social Security Scotland
  • pension or benefits summaries

You may be able to use the HMRC tax checker to estimate how much tax you should have paid in the previous tax year.

If you do not understand your calculation, you can get advice from HMRC or a professional, for example a tax advisor or accountant.

If you get state benefits

You can use your state benefit award letter to check the amount in the Simple Assessment is correct.

The payment frequency for state benefits can vary.

  1. Check your award letter for the relevant tax year to find out how much and how often you’re paid.

  2. If you’re paid every 4 weeks, multiply your payment by 13 (not 12) to get the annual amount. If you’re paid every 2 weeks, multiply your payment by 26. If you’re paid monthly, multiply your payment by 12.

  3. Check this amount against the amount in your Simple Assessment to make sure they’re the same.

If you get the State Pension, find out how your State Pension is taxed to check the amount in your Simple Assessment is correct.

Paying your tax bill

If the calculation is correct, you must pay the amount shown by the deadline on your Simple Assessment.

Find out how to pay your Simple Assessment tax bill.

View a printable version of the whole guide

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