CIS deadlines calendar
The CIS300 return is due by the 19th. The tax must reach HMRC by the 22nd if you pay electronically.
Every CIS tax month runs from the 6th to the 5th of the next month.
Since 6 April 2026, a month where you paid no subcontractors still needs a nil return, unless you have told HMRC you have stopped using subcontractors for a while.
| Tax month | Return due by | Pay HMRC by (electronic) |
|---|---|---|
| 6 Oct 2026 to 5 Nov 2026 | Thu 19 Nov 2026 | Fri 20 Nov 2026 * |
| 6 Nov 2026 to 5 Dec 2026 | Sat 19 Dec 2026 | Tue 22 Dec 2026 |
| 6 Dec 2026 to 5 Jan 2027 | Tue 19 Jan 2027 | Fri 22 Jan 2027 |
| 6 Jan 2027 to 5 Feb 2027 | Fri 19 Feb 2027 | Mon 22 Feb 2027 |
| 6 Feb 2027 to 5 Mar 2027 | Fri 19 Mar 2027 | Mon 22 Mar 2027 |
| 6 Mar 2027 to 5 Apr 2027 | Mon 19 Apr 2027 | Thu 22 Apr 2027 |
| 6 Apr 2027 to 5 May 2027 | Wed 19 May 2027 | Fri 21 May 2027 * |
| 6 May 2027 to 5 Jun 2027 | Sat 19 Jun 2027 | Tue 22 Jun 2027 |
| 6 Jun 2027 to 5 Jul 2027 | Mon 19 Jul 2027 | Thu 22 Jul 2027 |
| 6 Jul 2027 to 5 Aug 2027 | Thu 19 Aug 2027 | Fri 20 Aug 2027 * |
| 6 Aug 2027 to 5 Sep 2027 | Sun 19 Sep 2027 | Wed 22 Sep 2027 |
| 6 Sep 2027 to 5 Oct 2027 | Tue 19 Oct 2027 | Fri 22 Oct 2027 |
| 6 Oct 2027 to 5 Nov 2027 | Fri 19 Nov 2027 | Mon 22 Nov 2027 |
| 6 Nov 2027 to 5 Dec 2027 | Sun 19 Dec 2027 | Wed 22 Dec 2027 |
| 6 Dec 2027 to 5 Jan 2028 | Wed 19 Jan 2028 | Fri 21 Jan 2028 * |
| 6 Jan 2028 to 5 Feb 2028 | Sat 19 Feb 2028 | Tue 22 Feb 2028 |
| 6 Feb 2028 to 5 Mar 2028 | Sun 19 Mar 2028 | Wed 22 Mar 2028 |
| 6 Mar 2028 to 5 Apr 2028 | Wed 19 Apr 2028 | Fri 21 Apr 2028 * |
| 6 Apr 2028 to 5 May 2028 | Fri 19 May 2028 | Mon 22 May 2028 |
| 6 May 2028 to 5 Jun 2028 | Mon 19 Jun 2028 | Thu 22 Jun 2028 |
| 6 Jun 2028 to 5 Jul 2028 | Wed 19 Jul 2028 | Fri 21 Jul 2028 * |
| 6 Jul 2028 to 5 Aug 2028 | Sat 19 Aug 2028 | Tue 22 Aug 2028 |
| 6 Aug 2028 to 5 Sep 2028 | Tue 19 Sep 2028 | Fri 22 Sep 2028 |
| 6 Sep 2028 to 5 Oct 2028 | Thu 19 Oct 2028 | Fri 20 Oct 2028 * |
* The 22nd falls on a weekend or bank holiday that month, so the payment must clear on the working day before. Bank holidays are England and Wales. Dates worked out Wed 21 Oct 2026, using the same rules as the Subbo app.
How to send the CIS300
- Use HMRC's CIS online service, or CIS software from HMRC's list of suppliers.
- Give each subbie a payment and deduction statement within 14 days of the end of the tax month.
- Paying by cheque? It must reach HMRC by the 19th, not the 22nd.
What happens if you are late
- 1 day late: £100. 2 months late: another £200.
- 6 months late: £300 or 5% of the CIS deductions, whichever is higher. The same again at 12 months.
- Small contractors whose average monthly PAYE and CIS payments are under £1,500 may be able to pay quarterly. The return is still monthly.
See also: how to pay subcontractors under CIS.
Dates follow HMRC's CIS guide (CIS340) and gov.uk. Check anything unusual with your accountant or on gov.uk.
Never miss one
Subbo shows each month's CIS300 figures, reminds you before the 19th and the 22nd, and keeps the nil return in view. Free 8-week trial for a few friendly firms.
Free for 8 weeks. No card. No contract. The button opens your email app. Or write to harry@subboapp.com.