Owners often diary the year-end accounts deadline and assume tax can wait until then. For many limited companies, payment is due before the return. Missing that cash date is a different problem from filing late at Companies House.
This page is general information. Confirm your exact dates, amount and any instalment rules with your accountant and current GOV.UK corporation tax guidance.
YearReady™ helps you get the pack ready early so tax figures are not a last-minute reconstruction. Cashwatch™ puts the payment week on the same 13-week grid as debtors and VAT. Alfred prepares. A qualified professional signs off regulated tax work. Ask Alfred™ does not submit your CT600 or pay HMRC for you.
The usual payment deadline
For most companies that do not pay by instalments, corporation tax for an accounting period is due nine months and one day after the end of that period.
Example (illustrative only): if your accounting period ends on 31 March 2026, the usual payment date is 1 January 2027. Your accountant will confirm the date that applies to you.
Payment versus CT600 filing
| What | Typical timing for many companies |
|---|---|
| Corporation tax payment | Nine months and one day after the accounting period ends |
| CT600 return (filing) | Within twelve months of the accounting period ending |
| Companies House accounts | Often within nine months of the accounting reference date (separate from HMRC) |
Do not treat "I have a year to file the CT600" as "I have a year to pay". See what is a CT600 for the return itself, and Companies House late filing penalties for the accounts deadline.
When the simple rule may not apply
- Larger companies: some must pay by quarterly instalments. Your accountant will tell you if that regime applies.
- Short or long periods: first accounts after incorporation, or a change of year end, can shift dates.
- Payment plans or adjustments: HMRC arrangements change what leaves the bank and when.
If you are unsure which rules cover you, treat that as a question for a qualified professional, not a DIY guess.
Put the bill on your cash forecast
A tax bill that is "not yet filed" can still empty the bank in a quiet January. Add the expected payment to your 13-week grid as soon as you have a draft computation, or a cautious estimate from your accountant.
Read cash flow forecasting that includes tax and the cash flow forecast template UK. For the trough question, see when will my business run out of cash?
A calm prep checklist
Diary both dates: payment (often nine months and one day) and CT600 filing (often twelve months).
Start the year-end pack early with the UK year-end accounts checklist.
Ask for a draft tax figure before the payment week, not the week after.
Park the amount in Cashwatch or your forecast so other spend does not collide with HMRC.
Use Tax prep for the handoff: see Tax prep for checklist and accountant workflow.
Late payment is not the same as late filing
HMRC can charge interest and penalties for late corporation tax payments and for late returns. Companies House can charge separate penalties for late accounts. Being on time with one body does not clear the other. Confirm current consequences on GOV.UK and with your accountant.
What to read next
- What is a CT600
- UK year-end accounts checklist
- Cash flow forecasting that includes tax
- PAYE payment deadlines UK
- Companies House late filing penalties
- Corporation tax in the glossary
- YearReady™
- Cashwatch™
- Tax prep
This page is general information for UK limited companies. Deadlines, instalment rules and penalties can change. Check GOV.UK and your accountant for your situation. Nothing here is regulated advice, and nothing regulated should be submitted or paid on your behalf without human approval from a qualified professional.