Corporation Tax Instalment Payments Calculator
Calculate your CT instalment payment schedule — Small (lump sum), Large (quarterly in arrears) and Very Large (quarterly in advance).
CT Instalment Payments Calculator
England & Wales — Small / Large / Very Large companies
Your total Corporation Tax liability for the accounting period
Companies under common control (not counting your company itself). Default 0.
How CT instalment payments work
Whether a company pays CT in instalments depends on its augmented profits (CT liability adjusted for associated companies):
- Small (CT ≤ £1.5M adjusted): One lump sum, due 9 months and 1 day after the end of the accounting period.
- Large (CT £1.5M–£20M adjusted): Four quarterly instalments — months 7 and 10 of the current period, then months 1 and 4 of the next period.
- Very Large (CT > £20M adjusted): Four quarterly instalments in months 3, 6, 9 and 12 of the accounting period itself.
Associated companies rule
Both thresholds (£1.5M and £20M) are divided by the number of associated companies plus one. A company is associated if one controls the other or both are under common control.
Interest on underpayments
HMRC charges interest at the Bank of England base rate + 2.5% on underpaid instalments from the date they were due.
Disclaimer: This calculator is for guidance only. Always confirm your instalment obligations with your accountant or HMRC.