How to Submit a Quarterly Update to HMRC

Under Making Tax Digital, you submit a summary of your income and expenses to HMRC four times a year. AffordableMTD handles the entire process — you enter your figures (or import a spreadsheet), review the summary, and submit. Here's exactly how it works.

Before you submit

Make sure you've completed the initial setup: your HMRC account is connected, your NINO is entered, and your businesses have synced. Your dashboard will show your quarterly obligations with their deadlines.

Step 1: Select the quarter

On your dashboard, find the quarter you want to submit. Each obligation shows the period it covers (e.g. "6 April – 5 July 2026") and its deadline. Click Submit to start the process.

Step 2: Choose your quarter type (first time only)

Before your first submission of the tax year, you'll be asked to choose between:

• Standard quarters — Periods run from the 6th to the 5th (e.g. 6 April – 5 July). This is the default and aligns with the tax year.
• Calendar quarters — Periods run from the 1st to the end of the month (e.g. 1 April – 30 June). This can be simpler if your bookkeeping already follows calendar months.

This is a one-time election for the tax year. Once chosen, it applies to all four quarters. You can change it for the following tax year.

Step 3: Enter your income and expenses

You have two options for getting your data in:

Option A: Manual entry

Fill in the form with your income and expense figures. The form shows all the HMRC-recognised categories relevant to your business type (self-employment or property income). If your turnover is under £90,000, you can opt to enter a single consolidated expenses figure rather than breaking expenses into individual categories.

Option B: Import a CSV or Excel file

Upload your spreadsheet and let AffordableMTD map your columns to HMRC categories automatically. See How to Import Spreadsheets and CSV Files for a detailed walkthrough.

Step 4: AI review (optional)

Before submitting, you can run an AI review of your figures. This checks for common issues like:

• Unusually high or low figures compared to the period
• Missing income or expense categories you might have overlooked
• Potential disallowable expenses that should be separated out

The AI review is a helpful sanity check, not a requirement. You can skip it and go straight to submission if you're confident in your figures.

Step 5: Review your summary

You'll see a clear breakdown of everything you're about to submit:

• Total income — your turnover and any other income
• Total allowable expenses — broken down by category (or consolidated)
• Total disallowable expenses — if applicable
• Net profit — income minus allowable expenses

Check the numbers match what you expect. If anything looks wrong, go back and adjust before submitting.

Step 6: Submit to HMRC

Click Submit to HMRC. AffordableMTD sends your data directly to HMRC's MTD API. You'll see a confirmation screen once HMRC has accepted the update, including a timestamp and reference.

The submitted update will appear in your submission history, and the quarter's status on your dashboard will change to "Submitted".

After submission: your tax estimate

After processing your quarterly update, HMRC provides an estimated tax calculation based on your figures so far. You can view this within AffordableMTD. See Understanding Your Tax Calculation for what the numbers mean.

Common questions

What if I miss a deadline?

Submit as soon as you can. Under HMRC's points-based system, late submissions earn penalty points. However, the first year (2026-27) has a "soft landing" — no penalty points for late quarterly updates. For full details on how penalties work, see our penalties guide.

Do I need to submit for each business separately?

Yes — if you have both a sole trade and a rental property, each has its own set of quarterly obligations. You'll submit updates for each business independently.

How accurate do my quarterly figures need to be?

Quarterly updates are estimates. They don't need to be exact to the penny. You'll confirm your final, accurate figures in the end-of-year final declaration. That said, reasonable accuracy is expected — don't treat quarterly updates as guesses.