CIS Monthly Return Deadlines: A Contractor's Calendar

If you are a contractor in the Construction Industry Scheme, your monthly CIS return is due by the 19th of each month, and any deductions you owe must reach HMRC by the 22nd if you pay electronically. Both deadlines relate to the tax month that ended on the 5th, not to the calendar month.

Because the scheme runs every month of the year, a single late return is rarely the real problem — a habit of late returns is. This guide sets out the monthly cycle, gives you the dates for the rest of 2026, and shows how to build a routine that makes the 19th a non-event.

Key takeaways

• CIS tax months run from the 6th of one month to the 5th of the next.
• The monthly return is due by the 19th after the tax month ends.
• Deductions are paid with PAYE: by the 22nd electronically, or the 19th by post.
• Subcontractors must receive a payment and deduction statement within 14 days of the tax month ending.
• Months with no payments may still need a nil return or an inactivity notice.

What the CIS monthly return is

Under the Construction Industry Scheme, a contractor who pays subcontractors for construction work deducts money from those payments and passes it to HMRC as an advance towards the subcontractor's own tax. The monthly return is the contractor's report of who was paid, how much, and what was deducted during that tax month.

The deduction depends on the subcontractor's status: registered subcontractors usually have a standard rate deducted, unregistered ones a higher rate, and those with gross payment status have nothing deducted. You find out which applies by verifying each subcontractor with HMRC before you first pay them. The full list of contractor duties is on GOV.UK's guidance for CIS contractors.

The three monthly obligations compared

Your CIS calendar for the rest of 2026

• Tax month 6 August to 5 September 2026: return was due 19 September; electronic payment by Tuesday 22 September 2026.
• Tax month 6 September to 5 October 2026: return by Monday 19 October; electronic payment by Thursday 22 October 2026.
• Tax month 6 October to 5 November 2026: return by Thursday 19 November. The 22nd is a Sunday, so electronic payment needs to reach HMRC by Friday 20 November 2026.
• Tax month 6 November to 5 December 2026: return by Saturday 19 December; electronic payment by Tuesday 22 December 2026.
• Tax month 6 December 2026 to 5 January 2027: return by Tuesday 19 January; electronic payment by Friday 22 January 2027.

When a payment deadline falls on a weekend or bank holiday, the money needs to reach HMRC by the last working day before it. Remember that bank transfers can take time to clear. Ways to pay are listed on GOV.UK's pay employers' PAYE page, which also covers CIS deductions.

Months when you paid nobody

Quiet months are where contractors most often slip. If you made no payments to subcontractors in a tax month, you may still need to tell HMRC, either by filing a nil return or by notifying HMRC in advance that you will be inactive for a period. The rules on this have changed over the years, so check the current requirement on GOV.UK. What you should not do is simply skip the month and hope, because the system expects a return unless it has been told otherwise.

Step by step: a monthly CIS routine

1. Before paying anyone new, verify them with HMRC and record the deduction rate given.
2. Each time you pay, record the gross amount, any materials element and the deduction.
3. On the 6th, close off the tax month that ended the day before.
4. By the 10th, reconcile subcontractor invoices against bank payments.
5. By the 15th, issue payment and deduction statements to every subcontractor.
6. By the 17th, file the monthly return, leaving two days of margin.
7. By the 20th, pay HMRC so electronic funds arrive before the 22nd.

Worked example (illustrative example)

"Brookfield Roofing Ltd", an invented illustrative example, uses three regular subcontractors. In the tax month from 6 September to 5 October 2026 it pays all three, one of whom has gross payment status.

On 6 October the director closes the month and matches each invoice to a bank payment. One invoice shows labour and materials together; separating the materials element matters, because deductions are generally not made on the genuine cost of materials. Statements go to the two subcontractors with deductions by 15 October. The return, listing all three including the gross payment subcontractor, is filed on 16 October. Payment leaves the bank on 19 October and reaches HMRC comfortably before the 22nd.

In the following month, a quiet spell means no subcontractors are paid at all. Rather than ignoring it, the director checks the current nil return rules on GOV.UK and acts on them before the 19th. The company and its figures are invented to show the routine; your own position depends on your subcontractors and payments.

Common mistakes

• Working on calendar months. CIS runs 6th to 5th, so a payment on 3 October belongs to the September tax month.
• Deducting from materials. Deductions are generally made on the labour element only; keep evidence of genuine materials costs.
• Paying before verifying. Without verification you cannot know the correct deduction rate.
• Forgetting quiet months. No payments does not automatically mean nothing to file.
• Leaving statements until the subcontractor asks. They are due within 14 days whether or not anyone chases.

Getting CIS handled

Our CIS service starts from £40 per month and covers verification, monthly returns and subcontractor statements. If you also employ staff, CIS and PAYE are paid together, so it often makes sense to pair it with our payroll service — see the true cost of an employee for what payroll involves. Tidy records make every monthly return quicker, which is why our guide to bookkeeping vs doing it yourself is worth a read too.

Behind on CIS returns, or just want the 19th off your mind? Get in touch.