Corporation Tax Calculator 2024/25
Calculate your UK corporation tax bill and effective rate. Covers the small profits rate (19%), main rate (25%) and marginal relief for profits between £50,000 and £250,000.
Corporation Tax Calculator
Enter your taxable profit for the accounting year
Accounting profit adjusted for disallowables and capital allowances
Companies under common control — divides the £50k/£250k thresholds
Marginal Relief Reference Table (single company)
Effective rates for profits £50k–£250k
| Profit | Tax due | Effective rate |
|---|---|---|
| £50,000.00 | £9,500.00 | 19.00% |
| £75,000.00 | £16,125.00 | 21.50% |
| £100,000.00 | £22,750.00 | 22.75% |
| £125,000.00 | £29,375.00 | 23.50% |
| £150,000.00 | £36,000.00 | 24.00% |
| £175,000.00 | £42,625.00 | 24.36% |
| £200,000.00 | £49,250.00 | 24.63% |
| £225,000.00 | £55,875.00 | 24.83% |
| £250,000.00 | £62,500.00 | 25.00% |
R&D Tax Relief — April 2024 Merged Scheme
Most companies now use the merged RDEC scheme: a 20% above-the-line credit on qualifying R&D costs. Loss-making R&D-intensive SMEs (qualifying spend ≥ 30%) can claim 27%. Legacy SME scheme (pre-April 2024): enhanced deduction of 86% giving ~21.5% effective benefit.
Corporation Tax Rates 2024/25
The UK corporation tax system has three tiers from April 2023:
- Small profits rate (19%) — profits up to £50,000
- Marginal relief band — profits between £50,001 and £250,000 (effective marginal rate 26.5%)
- Main rate (25%) — profits over £250,000
Marginal Relief Explained
For profits in the £50,000–£250,000 band, marginal relief reduces the tax from the main rate. The formula is: Tax = 25% × profit − (3/200) × (£250,000 − profit). This creates an effective marginal rate of 26.5% within the band.
R&D Tax Reliefs
From April 2024, a merged R&D scheme applies a 20% above-the-line credit on qualifying R&D costs. Loss-making R&D-intensive SMEs (qualifying spend ≥ 30% of total costs) receive a higher 27% credit. Under the legacy SME scheme (pre-April 2024), the enhanced deduction was 86% of qualifying costs (giving an effective benefit of ~21.5% at the 25% rate).
FAQs
What counts as taxable profit?
Taxable profit is your accounting profit adjusted for disallowable expenses (e.g. client entertainment, depreciation replaced by capital allowances) and any available reliefs.
When is corporation tax due?
For most SMEs, corporation tax is due 9 months and 1 day after the end of the accounting period. Large companies (profits over £1.5M) pay in quarterly instalments.
Does marginal relief apply to associated companies?
Yes — the thresholds are divided by the number of associated companies plus one. Always confirm with your accountant if you have related entities.
What changed in April 2023?
The flat 19% rate ended. The main rate rose to 25% for large companies, with the small profits rate kept at 19% and marginal relief reintroduced for mid-range profits.