MTD ITSA: Prepare Your Records and Avoid Submission Errors

What MTD ITSA Requires From You

Making Tax Digital for Income Tax Self Assessment (MTD ITSA) replaces the traditional annual Self Assessment tax return for sole traders and landlords. Instead of one yearly submission, you now send quarterly updates to HMRC through MTD-compatible software, followed by a final end-of-period statement and a tax return to settle your bill. If your self-employment or property income exceeds £50,000, you are already in scope as of April 2026. The threshold drops to £30,000 from April 2027.

Set Up the Right Software Before Anything Else

HMRC does not accept spreadsheets alone. You must use software that is recognised by HMRC for MTD ITSA submissions. Popular options include QuickBooks, Xero, FreeAgent, and Sage. Some bridging software tools also allow spreadsheet users to remain compliant. Check the HMRC software finder tool to confirm your chosen product is approved. Sign up for MTD ITSA through your Government Gateway account and link it to your software before your first quarterly deadline.

How to Organise Your Records Quarterly

Each quarterly update covers a specific period. The four quarters run to 5 July, 5 October, 5 January, and 5 April, with submissions due one month after each period ends. You are not paying tax each quarter — you are simply reporting your income and expenses. Here is what to track consistently:

• Income: Record every payment received in the quarter, including late payments and any income in kind.
• Allowable expenses: Categorise costs correctly — office supplies, travel, professional subscriptions, software, and home office costs all need to sit in the right boxes.
• Mileage: If you use simplified expenses for vehicles, log each business journey with date, destination, and purpose.
• Receipts and invoices: Store digital copies. HMRC can ask to see supporting records, and paper receipts fade.

Common Submission Errors and How to Avoid Them

Most errors that trigger HMRC queries fall into a handful of categories. Being aware of them now will protect you later.

• Mixing personal and business expenses: Run a dedicated business bank account. Blending personal spending with business costs is the single most common source of errors and makes your quarterly figures unreliable.
• Missing the quarterly deadline: Late submissions attract penalties under the new points-based system. Each missed deadline earns a penalty point, and once you reach the threshold, a £200 fine applies. Diarise every deadline now.
• Incorrect expense categories: Claiming a laptop under travel costs or client entertainment under office expenses creates inconsistencies HMRC software flags automatically. Review your software's expense categories against HMRC guidance.
• Forgetting to reconcile your bank feed: If your software pulls in a bank feed, reconcile it weekly rather than in a panic before each deadline. Unreconciled transactions lead to duplicate entries or missing income.
• Not completing the end-of-period statement: Quarterly updates are not the finish line. You must submit your end-of-period statement to confirm your figures, add any adjustments such as capital allowances, and then file your final declaration. Skipping this step leaves your tax position open.

Transitional Relief and What It Means for You

HMRC introduced a penalty waiver during the first year of MTD ITSA to give businesses time to adjust. However, this relief covers only late filing penalties, not errors in the figures you submit. Submitting inaccurate data could still trigger an enquiry. Use the transitional period to build solid habits rather than treating it as permission to be careless.

Start Now, Not in September

The freelancers who struggle most with MTD ITSA are those who try to reconstruct three months of transactions the week before a deadline. Spend thirty minutes each week logging income, categorising expenses, and reconciling your bank feed. By the time your quarterly deadline arrives, your submission should take under an hour. Good record-keeping is not just a compliance requirement — it gives you a real-time view of your tax liability so there are no nasty surprises in January.