CIS deadline reminders
Your CIS return is due by the 19th of every month. See your next deadline below, and get a free email about a week before each one.
Your next CIS deadline
Your next return covers 6 October to 5 November. It has to reach HMRC by 19 November 2026. If you have deductions to pay over, the money has to reach HMRC by 20 November 2026, which is earlier than the usual 22nd because that date is not a banking day.
Filing and paying are two different deadlines. Treating them as one is the commonest way to be late.
| Deadline | Date | What it is |
|---|---|---|
| Tax month ends | 5 November 2026 | The period your return covers |
| Return due | 19 November 2026 | Your CIS300 has to have reached HMRC. £100 penalty the day after |
| Deductions due | 20 November 2026 | The money itself. Earlier than the 22nd this month, because the 22nd is not a banking day |
Sign up now and your next reminder goes out on 12 November 2026, for the return due 19 November 2026.
When is the CIS return due?
By the 19th of every month, for the tax month that ended on the 5th. A tax month runs from the 6th to the 5th, so the return for 6 October to 5 November is due on 19 November 2026. The 22nd is a different date: it is when the tax you took off subcontractors has to reach HMRC.
More on the return itself in our guide to CIS returns.
What if the 19th is a weekend?
The deadline stays the 19th. A return that arrives on the Monday is late. The next one to watch is the return for 6 November to 5 December, due Saturday 19 December 2026.
The payment date does move, and it moves earlier. If the 22nd is a weekend or bank holiday, the money has to arrive on the banking day before.
What happens if I am late?
The penalty is £100 the day after the deadline, and it grows the longer the return is outstanding:
- 1 day late: £100
- 2 months late: £200
- 6 months late: £300 or 5% of the CIS deductions on the return, whichever is higher
- 12 months late: £300 or 5% of the CIS deductions on the return, whichever is higher
- Later than 12 months: an additional penalty of up to £3,000 or 100% of the CIS deductions on the return, whichever is higher
What one late CIS return costs, month by month
Think a penalty is unfair? Read how to appeal a CIS penalty.
Do I need to file a nil return?
Yes. Since 6 April 2026, if you paid nobody in a tax month you still have to file, or tell HMRC in advance that the scheme is inactive. The penalty for missing it is the same £100.
What does the reminder email say?
It comes from Quids Bookkeeping, about a week before the deadline, once the tax month has closed. It gives you:
- The deadline, and the period the return covers
- The separate date the deductions are due
- What to have ready, including the labour and materials split
- A reminder that a nil return still counts
Can I stop the reminders?
Yes, in one click. Every email has an unsubscribe link at the bottom. The reminder is free, you do not have to be a client, and we only use your address to send it. You can also email [email protected].
Primary sources and further reading
If HMRC and this page ever disagree, HMRC is right.
Have your CIS return ready before the 19th, every month
The reminder is the free version. We prepare your CIS300 before the 19th, ready for you to check and submit. Join the waitlist for 2027.