Submit your tax return
Source: gov.uk (2025-09-03)

How to complete and submit your tax return using software that works with Making Tax Digital for Income Tax.

Once you have made all the adjustments to your self-employment and property income and expenses (https://www.gov.uk/guidance/use-making-tax-digital-for-income-tax/adjust-your-self-employment-and-property-income), you will need to use your software to:
- complete your tax return
- submit your tax return
You must submit your tax return by 31 January following the end of the relevant tax year, but you can submit it earlier than this. For example, you can submit your tax return for the 2025 to 2026 tax year any time after 6 April 2026, but you must submit it by 31 January 2027.

If you miss the deadline for submitting your tax return, then you will be liable for a late submission penalty point (https://www.gov.uk/guidance/penalties-for-income-tax-self-assessment-volunteers).

Add your other sources of income and gains

You need to make sure all your other taxable sources of income or gains for the year are included in your software that works with Making Tax Digital for Income Tax (https://www.gov.uk/guidance/find-software-thats-compatible-with-making-tax-digital-for-income-tax).

For Making Tax Digital for Income Tax, different information about your other income sources will be added by you and by HMRC. You need to check that all information added is correct.

Information HMRC will add

If HMRC already has information about your other sources of income and gains, we will add this into your tax return. This includes:
- employment (PAYE) income
- student loan repayments
- income from state, private and occupational pensions
- other taxable state benefits
- Construction Industry Scheme (CIS) — subcontractor deductions
- Capital Gains Tax residential property disposals
- Marriage Allowance claims
After HMRC have added this information, you can find it in either your:
- software, when you ask the software for a calculation
- HMRC online services account
Information you will add

You still need to add other income sources into your tax return if you have not added them during the tax year and you need to declare them. For example:
- savings and dividends
- any other income or gains that have not been automatically added
You need to add this information before you submit your tax return.

Check your information

Before you submit your tax return, check that the information added by you and HMRC is correct.

If something is incorrect or you need to update it, you can add the correct information, and this will overwrite the previous information.

Your information is only treated as final once you have submitted your tax return.

Submit your own tax return

You need to submit your tax return through your software that works with Making Tax Digital for Income Tax.

You need to confirm in your software that:
- you’re ready to submit your return
- you agree with the calculation given in your software for tax due
You will also need to declare that the information you have provided is correct and complete to the best of your knowledge.

You should only do this after you’ve added all of your income sources and gains, and checked that all of your information is correct.

Go into your software and confirm you’re ready to submit your tax return.

View the calculation in your software that shows you the amount of tax due.

Check the calculation is correct.

Submit your tax return by declaring that your information and calculation is correct.

You’ll then see a message in your software to tell you your tax return has been submitted.

Submit your client’s tax return

You need to submit your client’s tax return through software that works with Making Tax Digital for Income Tax. You can only do this if you are your client’s main agent (https://www.gov.uk/guidance/choose-agents-for-making-tax-digital-for-income-tax).

If your client, or a supporting agent, has sent quarterly updates or added other income sources and gains, you can view and check these details in your software, but you will not be able to view their digital records.

You should speak to your client, or their supporting agent, if you need to access or make any corrections to their digital records (https://www.gov.uk/guidance/use-making-tax-digital-for-income-tax/create-digital-records).

When you’ve added all your client’s income and gains and checked everything is correct, you’re ready to submit your client’s tax return.

Go into your software and confirm you’re ready to submit your client’s tax return.

View the calculation in your software that shows you the amount of tax due.

Check the calculation is correct.

Share a copy of the calculation with your client and confirm with them they agree with it.

Submit your client’s tax return by declaring that the information and calculation is correct to the best of your knowledge.

You’ll then see a message in your software to tell you your client’s tax return has been submitted.

If you disagree with the calculation or there is an error in your software

You should check the information you’ve added in your software. If there is an error, you can correct it in your software before you submit your tax return.

If your software does not give you a calculation when you ask for one, there is an error. Your software should explain what to do next. If it does not, contact your software provider for support.

If you’re volunteering to test Making Tax Digital for Income Tax

If you disagree with the calculation your software shows you when you go to submit your tax return, you can contact the dedicated customer support team for help.

If your software does not support submission of your other income sources

You may be volunteering to test the service before 6 April 2026.

If your current software does not support the submission of your other income sources, ask your software provider if they will be adding this to your software and by when.

If they are not adding this function or if it will not be in place before you need to submit your tax return, you can either:
- choose alternative or additional software that works with Making Tax Digital for Income Tax, which will support the submission of your other income sources
- contact the dedicated support team for Making Tax Digital for Income Tax (https://www.gov.uk/guidance/use-making-tax-digital-for-income-tax/help-and-support)
After you have submitted your tax return

If you need to correct or include something else, you can amend your return (https://www.gov.uk/guidance/use-making-tax-digital-for-income-tax/if-your-circumstances-change).

The information you give to HMRC will generate your Self Assessment tax bill for that tax year.

Making Tax Digital for Income Tax will not change the way you pay tax or the dates that payments are due. If you do not pay your Self Assessment tax bill (https://www.gov.uk/pay-self-assessment-tax-bill) by the relevant deadlines, you will be liable to pay a late payment penalty (https://www.gov.uk/guidance/penalties-for-income-tax-self-assessment-volunteers).