Your MTD
questions, answered.

Before you start

• Ensure both you (the agent) and your client are registered for Making Tax Digital (MTD) with HMRC.
• Check that your client’s National Insurance number is entered correctly within Practice Manager.
• Log in using your Agent Services Account (ASA) credentials, not GOV.UK One Login.

Only self-employment, UK property, and foreign property income count. Partnership income, PAYE/employment income, and dividends do not count towards qualifying turnover for MTD.

Yes, linking is strongly recommended. Without it, you won't see obligation periods, due dates, or submission status for that business.

Use the "Link Businesses" button on the Business Information page. If a business already exists in the client record, link to that existing business rather than creating a new one. Sign in with your agent services account (ASA) credentials.

If there are no business records in TaxCalc for the individual, you can either create the business in Practice Manager using the 'Add a business' button in MTD, or, fetch the businesses directly from HMRC.

Please note, if an existing business has already been created within the client record please ensure you link to this business when you fetch from HMRC.

There's no right or wrong answer, but be consistent throughout the year. It doesn't affect the upload process or due dates, it only tells HMRC which date range you're reporting on (5th of month vs. end of month). If a client already prepares accounts to 5 April, "Standard" often ties in more naturally; if they're VAT registered, "Calendar" may align better with existing records.

See the key quarterly filing dates

No, regardless of basis, it's still a simple bridging/spreadsheet upload process.

Only the Totals tab needs mapping. You don't need to map the Sales or Purchases tabs individually; those feed into the Totals page automatically via formulas.

This is your choice, but businesses with expected turnover above £90k for the year should be using a detailed submission. For people with lower turnover values, it is optional.

Yes, and you should. MTD figures are cumulative (unlike VAT), so each submission should contain the full year-to-date data in one continuous spreadsheet, not separate spreadsheets per quarter.

Yes, always use "Save a Copy" when uploading. This keeps a record of exactly what was submitted at that point in time.

Separately. The tax adjustments/disallowable box excludes CIS. CIS still requires its own separate submission to HMRC when trigger calculation is done and can be amended at the year end as part of the final tax return, not on a quarterly basis.

No, capital allowances are dealt with at year end as part of the final tax return, not on a quarterly basis.

You have two options: resubmit the same period in full, or include the correction/amendment in the next submission. There's no tax payable at this stage, it's a reporting exercise, so errors can be corrected later.

Don't delete it from the MTD screen. Delete it from the client record in Practice Manager (Business tab). If you simply want to show it as linked, go through the linking process instead.

If the business does not delete then please see our article on known errors.

It's HMRC's own inbuilt estimate, not TaxCalc's. It reflects everything HMRC has received so far, including submissions made via other MTD software or CIS. If HMRC's system is under maintenance, this may temporarily fail to pull through.

Each individual only reports their own share on their own submission, e.g. 50/50 joint owners would each report 50% on their respective returns.

No, you can drag and drop multiple cells into the same category (e.g. two different cost lines both mapped to "Cost of Goods Sold"). Once mapped, you can save the mapping template and reuse it across clients using the same layout.

Yes, it's recommended. This makes the year-end fetch function easier and ensures the business is ready in TaxCalc if you ever need to step in or prepare accounts.

No, MTD sign-up is the client's (or agent's, on their behalf) responsibility. HMRC will not auto-enrol anyone, and non-compliance can trigger penalty points.

Once linked, TaxCalc will show those earlier periods as "fulfilled," but you won't see the underlying submission detail. Only submissions made directly through TaxCalc show full history.

Yes, it's available now in TaxCalc and is being rolled out in phased releases.

See MTD Individual Tax Returns – what will be available to enter for 2025/26.

Yes, when linking a business, you'll be prompted to sign in, allowing you to select the correct agent credentials for that particular client/office.

No, SA100 is separate to MTD.

The SA100 is the traditional, paper or online annual Self Assessment tax return form. Making Tax Digital (MTD for ITSA) is a newer digital system that replaces that old annual return with frequent digital updates.