If you are a CIS subcontractor, Making Tax Digital for Income Tax applies once your gross turnover is over £50,000 for 2024/25, £30,000 for 2025/26 or £20,000 for 2026/27. CIS deductions go into your quarterly updates; contractors still file monthly.
The limit is tested against your qualifying income — self-employment plus property, before expenses — for 2024/25, 2025/26 and 2026/27 respectively.
Source: Find out if and when you need to use Making Tax Digital for Income Tax — gov.uk (opens in a new tab)HMRC says that once Making Tax Digital applies, subcontractors include any CIS deductions in their quarterly updates, and that some software handles the deductions automatically.
Source: Making Tax Digital for Income Tax: frequently asked questions — HMRC campaign site (opens in a new tab)A contractor registered with the scheme still sends CIS returns every month. HMRC suggests asking software providers about products that handle both CIS and Making Tax Digital.
Source: Making Tax Digital for Income Tax: frequently asked questions — HMRC campaign site (opens in a new tab)Qualifying income is your income from self-employment and property before expenses. HMRC's guidance does not mention CIS deductions, so use the gross figure on your payment and deduction statements.
Source: Work out your qualifying income for Making Tax Digital for Income Tax — gov.uk (opens in a new tab)Standard quarters end 5 July, 5 October, 5 January and 5 April; calendar quarters are also allowed. Each update is cumulative from the start of the tax year.
Source: Send quarterly updates — Use Making Tax Digital for Income Tax — gov.uk (opens in a new tab)CIS deductions are tax your contractor has already paid to HMRC on your behalf, taken from your payments at 20% or 30% depending on your registration. They are a payment on account, not an expense. Our reading of HMRC's guidance is therefore to use the gross amount invoiced to contractors when you test yourself against the limit, not the lower amount you were paid.
HMRC's published guidance does not address CIS deductions in the qualifying-income test directly. If you are close to a limit, confirm with HMRC or your accountant before relying on any estimate, ours included.
Your contractor must give you a payment and deduction statement for each payment. Under MTD for Income Tax you need digital records of your income and expenses, and your supporting documents, kept for at least five years after the 31 January deadline.
If a contractor's figure and yours disagree, resolve it with the contractor. A deduction you cannot show on a statement is one you are unlikely to get credit for.
Four times a year you send HMRC the totals for each income and expense category, by 7 August, 7 November, 7 February and 7 May. Updates are cumulative from the start of the tax year and you do not make tax adjustments first. After the fourth update you check your figures and finish the year-end step by 31 January.
If you are not yet mandated, you claim back over-deducted CIS tax on your Self Assessment return. ac-co's Self Assessment product is live and HMRC-recognised for the SA100: it claims your 20% or 30% deductions through box 38 of the SA103S and shows a labelled refund estimate.
ac-co Income Tax (MTD) is in open beta: it drafts quarterly updates from your connected bank and books, but live filing to HMRC is not open yet. ac-co's CIS product is on the waitlist; it captures payment and deduction statements into a register and estimates your refund, and it does not file anything. Use software from HMRC's list for any real deadline that falls before live filing opens.
Prepared from your connected bank and books, for you to review.
The records behind each figure, kept digitally.
What is due, and what it means for your bill.
In open beta: drafted for you to review. Live filing to HMRC is not open yet.
Enter your gross self-employment turnover, before CIS deductions and expenses. The checker tests it against all three limits using the same engine as our eligibility calculator.
An estimate from the figures you enter, not advice. HMRC decides who is in scope, using your Self Assessment return.
Subcontractors with qualifying income over £50,000 for 2024/25 had to start on 6 April 2026. The limit is £30,000 for 2025/26 income and £20,000 for 2026/27 income.
HMRC says subcontractors include any CIS deductions in their quarterly updates, and that some software does this automatically. Ask your software provider how it handles them.
No. HMRC says a contractor registered with the scheme still sends CIS returns every month. You can use software that handles both CIS and Making Tax Digital.
HMRC counts income before expenses. Its guidance does not mention CIS deductions, so our reading is to use your gross turnover. Confirm with HMRC or your accountant if you are close to a limit.
Yes. If you are not yet mandated you claim over-deducted CIS tax on your Self Assessment return, where it goes in box 38 of the SA103S. Mandated subcontractors have the deductions in their quarterly updates.
Not yet. ac-co Income Tax (MTD) is in open beta and live filing to HMRC is not open. The CIS product is on the waitlist and does not file anything. Join the waitlist and we will tell you when that changes.
Read on 12 October 2026. HMRC changes its guidance; check the page itself for anything that may have moved since.
ac-co Income Tax (MTD) is in open beta. Join the waitlist and we will open seats in batches.