How much is the fine for a late CIS return?

£100 the day after the 19th. If the return still isn't in 2 months later, another £200. At 6 months and again at 12 months, £300 each, or 5% of the CIS deductions on the return if that's more. If you'd filed a CIS return by its deadline, a return a year late costs at least £900.

Do I get fined for a late nil return?

Yes. Since 6 April 2026 a late nil return gets the same penalties, and with no deductions the 6 and 12 month penalties are £300 each. You don't need a nil return for a month if you told HMRC at least 14 days before it started that you wouldn't pay any subbies in it.

Do the penalties stop once I file?

Yes. Each later penalty is only charged if the return still isn't filed on its date, so filing stops the next one. Penalties already charged stay.

Can I appeal a CIS late filing penalty?

Yes, within 30 days of the date on the penalty notice. There's no penalty if you had a reasonable excuse and filed without unreasonable delay once it ended. Not having the money, or relying on someone else to file, doesn't count on its own.

CIS penalty calculator

See what a late CIS return costs and the date each penalty is charged: £100 the day after the 19th, then more at 2, 6 and 12 months. Free, no account, and nothing you type is stored or sent.

What the late return costs

Penalties charged: £300.00; Due by 19 Jul 2026

Filed late. Nothing more is added once the return is in.

Each CIS late filing penalty on this return, the date it is charged and whether it applies
Penalty	Charged on	Amount
£100 late filing penaltyCharged	20 Jul 2026	£100.00
£200 at 2 monthsCharged	20 Sep 2026	£200.00
£300 or 5% at 6 monthsNot charged	20 Jan 2027	£300.00
£300 or 5% at 12 monthsNot charged	20 Jul 2027	£300.00

The calculator assumes the return was late, not held back on purpose. For what HMRC charges when it was, see CIS late filing penalties.

How CIS late filing penalties are worked out

Your CIS300 is due by the 19th. If it isn't in by then, each of these is added to the one before:

£100 on the 20th, the day after the deadline.
£200 if the return still isn't filed on the 20th two months later. A return due on 19 November that goes in on 19 January escapes it; filed on 20 January, it doesn't.
At 6 months, £300 or 5% of the CIS deductions on the return, whichever is more.
At 12 months, the same again.

The calculator rounds the 5% down to the penny. Once the return is filed, nothing more is added.

CIS penalty worked example

The return for 6 Sep 2026 to 5 Oct 2026 is due by 19 Oct 2026. If it's still not filed a year later, and you'd filed a CIS return by 19 Oct 2026, the penalties are:

CIS late filing penalties on one return, with £2,400 and with £10,000 of deductions
Penalty	Charged on	£2,400.00 deducted	£10,000.00 deducted
£100 late filing penalty	20 Oct 2026	£100.00	£100.00
£200 at 2 months	20 Dec 2026	£200.00	£200.00
£300 or 5% at 6 months	20 Apr 2027	£300.00	£500.00
£300 or 5% at 12 months	20 Oct 2027	£300.00	£500.00
Total		£900.00	£1,300.00

5% of £2,400.00 is £120.00, less than £300, so the £300 applies. 5% of £10,000.00 is £500.00, so that's charged instead.

CIS penalties on your first returns

If you've never filed a CIS return, your first one, and any that were due before you filed it, are treated more gently. There's no £300 minimum at 6 and 12 months, so those penalties are just 5% of the deductions, and nothing on a nil return.

The £100 and £200 penalties across all those returns are capped at £3,000 in total. The calculator works out one return at a time, so it shows the cap rather than applying it. Answer "No" to "Had you filed any CIS return by this one's deadline?" to see those rules.

CIS penalties on a late nil return

Since 6 April 2026, a late nil return gets the same penalties. Leave the deductions blank: the 6 and 12 month penalties are then £300 each, or nothing on a first return.

You don't need a nil return for a month if you told HMRC at least 14 days before it started that you wouldn't pay any subbies in it. See CIS nil returns.

CIS penalty questions

How much is the fine for a late CIS return?: £100 the day after the 19th. If the return still isn't in 2 months later, another £200. At 6 months and again at 12 months, £300 each, or 5% of the CIS deductions on the return if that's more. If you'd filed a CIS return by its deadline, a return a year late costs at least £900.
Do I get fined for a late nil return?: Yes. Since 6 April 2026 a late nil return gets the same penalties, and with no deductions the 6 and 12 month penalties are £300 each. You don't need a nil return for a month if you told HMRC at least 14 days before it started that you wouldn't pay any subbies in it.
Is it different if it's my first CIS return?: Yes, it's less. On your first return, and any that were due before you filed it, there's no £300 minimum at 6 and 12 months, so those penalties are just 5% of the deductions. The £100 and £200 penalties on all those returns together are capped at £3,000.
Do the penalties stop once I file?: Yes. Each later penalty is only charged if the return still isn't filed on its date, so filing stops the next one. Penalties already charged stay.
Can I appeal a CIS late filing penalty?: Yes, within 30 days of the date on the penalty notice. There's no penalty if you had a reasonable excuse and filed without unreasonable delay once it ended. Not having the money, or relying on someone else to file, doesn't count on its own.

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CIS late filing penalties
What a late return costs, and what makes it more
CIS deadlines
Return by the 19th, payment by the 22nd if paid electronically
CIS nil returns
When you need one, and how to tell HMRC in advance you won't pay any subbies

All guides