Period & profit
Corporation Tax due
£17,450.00
After £2,550 reliefPeriod 01/04/2026 – 31/03/2027
Marginal relief
£2,550.00
FY 2026 · 3/200 fraction
Effective rate
21.81%
−3.19pp vs main rate
Period breakdown
| Period | Profit | Rate | Tax | Marginal relief | Net tax |
|---|---|---|---|---|---|
| 01/04/2026 – 31/03/2027 FY 2026 | 80,000.00 | 25.00% | 20,000.00 | 2,550.00 | 17,450.00 |
| Total | 80,000.00 | — | 20,000.00 | 2,550.00 | 17,450.00 |
Marginal relief workings
Marginal relief applies where augmented profits fall between the lower and upper limits:
(
Upper limit
−
Augmented profits
)
×
(
Taxable profits
÷
Augmented profits
)
×
Marginal relief fraction
Apportionment basis
Days in the financial year
365
Days in this accounting period
365
Associated companies
Including this company
1
Marginal relief limits (£)
Lower limit
50,000 × 365 ÷ 365
50,000.00
Upper limit
250,000 × 365 ÷ 365
250,000.00
Profits (£)
Taxable profits
80,000.00
Augmented profits
Taxable + non-group dividends received
80,000.00
Relief calculation (£)
Upper limit
250,000.00
Less: augmented profits
(80,000.00)
Margin below the upper limit
170,000.00
Proportion chargeable
Taxable ÷ augmented profits
1.0000
Marginal relief fraction
3/200 (FY 2026)
0.0150
Marginal relief for FY 2026
£2,550.00
Estimate only. Figures are based on HMRC's published rates
and assume a single trading entity with no group surrender, no R&D credits
and no chargeable gains. For a binding calculation, run a full CT600 in
your dashboard.
Need a full CT600 submission?
This estimator is for guidance only. Sign up for the Tax Optimiser dashboard to file a binding Corporation Tax return with HMRC, with full working papers and integration to your bookkeeping software.
Sign up free