Quick compliance check

Use this quick reference to verify your Corporation Tax obligations are on track. Each section links to detailed guidance if you need more information.

Deadlines

File your Company Tax Return (CT600)

Filing requirements, iXBRL format, and how to submit.

Rates and thresholds

Current Corporation Tax rates

Verify which rate applies to your company based on taxable profits and associated companies.

Main rate (25%): Applies to profits over £250,000 (from 1 April 2023)
Small profits rate (19%): Applies to profits of £50,000 or less
Lower threshold: £50,000 (small profits rate eligibility)
Upper threshold: £250,000 (main rate applies above this)
Marginal relief band: £50,000 to £250,000 (tapered effective rate 19%-25%)
Associated companies rule: Thresholds divided equally by number of associated companies

The Corporation Tax rate structure changed significantly from 1 April 2023 under Finance Act 2022. The main rate increased from 19% to 25% for profits over £250,000, while small companies with profits up to £50,000 retained the 19% rate. Companies with profits between £50,000 and £250,000 benefit from marginal relief, which provides a gradual transition between the two rates.

Associated companies: If you have associated companies (connected businesses under common control), the profit thresholds are divided equally by the total number of companies. For example, with 2 associated companies, the small profits threshold becomes £25,000 each.

Corporation Tax rates (opens in a new tab)

Corporation Tax rates and small profits relief

Full rate tables, marginal relief formula, and associated companies impact.

Payment

Plan your Corporation Tax payments

Payment methods, quarterly instalments for large companies, and Time to Pay.

Quarterly instalment threshold

Check if your profits exceed the quarterly instalment threshold, adjusted for associated companies.

Large companies must pay Corporation Tax in quarterly instalments rather than in one lump sum. This significantly affects cash flow planning and is often missed by growing businesses crossing the £1.5m threshold for the first time.

Threshold for quarterly instalments: £1.5 million annual profits
Associated companies rule: £1.5m threshold divided equally (e.g., 2 associated companies = £750,000 threshold each)
Very large companies threshold: Profits over £20 million (earlier payment schedule applies)
Amount per instalment: 25% of estimated annual Corporation Tax liability

Payment schedule for £1.5m-£20m profits

Companies with profits between £1.5 million and £20 million must pay Corporation Tax in quarterly instalments on the following schedule:

Instalment 1: Month 7 of accounting period (14 days after end of month 6)
Instalment 2: Month 10 (14 days after end of month 9)
Instalment 3: Month 13 (1 month and 14 days after period end)
Instalment 4: Month 16 (4 months and 14 days after period end)

Example: Company with December year-end and £2m profit

Estimated Corporation Tax: £2m × 25% = £500,000
Per instalment: £500,000 ÷ 4 = £125,000
Instalment 1: 14 July (while still trading - 6 months before year-end)
Instalment 2: 14 October
Instalment 3: 14 February (after year-end)
Instalment 4: 14 May

Cash flow impact: You pay significant Corporation Tax before the accounting period ends - when cash may be tied up in stock, debtors, or reinvested in growth.

Very large companies (over £20m profits)

Companies with profits over £20 million must pay instalments even earlier - starting in month 7 of the accounting period (compared to month 14 for companies in the £1.5m-£20m bracket).

Important: You must estimate profits accurately. HMRC charges interest if you underpay instalments. Missing instalments triggers automatic interest charges (even if unintentional).

Corporation Tax quarterly instalment payments (opens in a new tab)

Allowances and reliefs

Claim capital allowances for your company

AIA, full expensing, and writing down allowances - claim order matters.

Full checklist

Corporation Tax annual compliance checklist

Complete year-end checklist covering accounts, filing, payment, and record keeping.

Corporation Tax quick compliance check

Quick compliance check

Deadlines

File your Company Tax Return (CT600)

Rates and thresholds

Corporation Tax rates and small profits relief

Payment

Plan your Corporation Tax payments

Allowances and reliefs

Claim capital allowances for your company

Full checklist

Corporation Tax annual compliance checklist

Related journeys

File your first Corporation Tax return

Manage your tax compliance

Respond to a Corporation Tax penalty or enquiry

Set up a limited company