How do I submit a quarterly update to HMRC as a builder?

Your software sends HMRC your turnover, in our reading your pay before CIS deductions, and your costs, as totals for the year so far. If you start on 6 April 2027, your first update is due by 7 August 2027.

Making Tax Digital for Income Tax (MTD) asks every sole trader for the same thing each quarter: category totals, not receipts. What makes a builder's update different is the Construction Industry Scheme (CIS). The money in your bank is not your turnover, and the deductions taken off it do not go in the update at all. This page follows GOV.UK's MTD and CIS guidance, HMRC's quarterly update direction and HMRC's tax return notes, checked on 17 October 2026. The general guide covers sending an update for everyone.

Who sends them, and when

You join when your qualifying income, which is self-employment and property income before expenses, goes over the line. Over £50,000 in 2024-25 meant starting on 6 April 2026. Otherwise, over £30,000 in 2025-26 means 6 April 2027, and failing that, over £20,000 in 2026-27 means 6 April 2028. Wages from a PAYE job do not count. For a subcontractor, the test uses pay before CIS deductions, as the turnover guide explains.

Calendar periods ending 30 June, 30 September, 31 December and 31 March have the same deadlines. Choose them in your software before your first update of the year.

Where CIS fits

Turnover is gross. HMRC's notes for the self-employment tax return pages say a subcontractor's turnover is "the full amount (before Construction Industry Scheme (CIS) deductions made by contractors)". GOV.UK says MTD uses the same income and expense categories as Self Assessment, so in our reading the same gross figure goes in your update. GOV.UK also warns that some transactions do not appear in full in a bank feed. A CIS payment is one of them: the bank shows the net amount, and your monthly statement shows the gross.

Deductions stay out. The update carries turnover, other business income and expense totals. HMRC's technical specification has a box for "other tax taken off trading income apart from CIS deductions", and no box for CIS itself. Your deductions count at the end of the year: HMRC adds the CIS subcontractor deductions it holds to your MTD tax return, and you check them against your statements before you submit.

Materials. Contractors do not take the deduction from materials you paid for directly. In our reading, the materials you charge for are part of your turnover, and what you paid for them goes in "cost of goods bought for resale or goods used", which HMRC's notes say includes raw materials.

Your own subbies. If you pay other subcontractors, HMRC's direction gives payments to construction industry subcontractors their own expense category.

Turnover under £90,000. GOV.UK lets a sole trader with turnover under £90,000 from that trade record each item as just income or an expense. HMRC's specification then accepts a single expenses total. If you reach £90,000, every record for the year must be fully categorised before your next update.

A worked example

A self-employed bricklayer starts MTD on 6 April 2027. Between 6 April and 5 July 2027 he invoices a contractor £9,000 for labour and £2,000 for blocks and mortar he bought. The contractor takes 20% from the labour only, £1,800, and £9,200 reaches his bank.

If July to October brings another £12,000 gross, his second update shows turnover of £23,000, because it covers the year so far. This is an example only.

What this means for you

The work is in matching your records to your monthly CIS statements. Record each job's gross pay as income and each deduction separately, so the totals in your update are right and the deductions are ready for your tax return. If a statement arrives late, add it and the next update picks it up. From 2027-28, if you must use MTD, each missed deadline earns a penalty point, and 4 points brings a £200 penalty. GOV.UK says you cannot claim a tax refund in an MTD tax return, so if your deductions come to more than your bill, the CIS refund guide shows the separate route.

Steps to send your update as a builder

1. Collect every monthly payment and deduction statement for the period, and chase any contractor who has not sent one.
2. Record each payment at its gross amount as income, and note the deduction alongside it.
3. Record materials, van, tools and other costs with the amount, date and category.
4. After the period ends, check that your turnover matches the gross pay on your statements, not your bank.
5. Send the update from your software by the deadline, even after a quarter with no work.
6. After the fourth update, check the CIS deductions HMRC adds to your tax return against your statements, then submit by 31 January.

The free MTD check shows when you start, and the trades section has more guides on CIS and MTD.