MTD Individual Tax Return - how does the process work as compared to the SA100?

The MTD tax return, as opposed to the SA100, is required to be completed for individuals who have registered for MTD for income tax for the tax year.

It can only be prepared digitally and is due by 31 January following the end of the tax year (same as the existing SA100). The process itself is very different in that communication with HMRC works both ways throughout the whole process.

Key differences:

• The NI number is key rather than the UTR
• Connection and authorisation for filing is via the token method and not via HMRC government gateway user ID and password
• The data can be updated to HMRC throughout process, before finalising and not all at once
• It is possible to retrieve HMRC tax calculations throughout the process, as data is updated

The data included within the return will include:

• Quarterly submitted data for businesses
• Amendments and accounting adjustments made to quarterly submitted data
• Non-business income (e.g. savings, dividends, employment)
• Reliefs and allowances
• Final declaration to confirm the information is complete and accurate
• Confirmation of the final tax position

The TaxCalc journey

The MTD individual tax return (ITR) forms part of the same licence for Tax Return Production (TRP). With a TRP licence a return can be created for an individual as either a SA100 or MTD ITR for the tax year (it is not possible to have both). The entry screens will look familiar from SimpleStep, with more detail required by HMRC in certain areas.

Once a return has been created we would expect the completion to follow the steps below:

Once the return has been submitted and fulfilled, amendments can be made by following steps 7 to 10 again (functionality to come in October 2026 release)

Related articles

MTD Individual Tax Returns - guide for completing self-employment sections

MTD Individual Tax Returns - what will be available to enter for 2025/26