Corporation Tax calculator 2026/27
Use this calculator to estimate your UK limited company's Corporation Tax for the 2026/27 tax year. Enter your taxable company profit and the number of associated companies. The calculator applies the small profits rate, main rate and marginal relief where relevant.
2026/27 UK ratesRates checked 16/09/2026No sign-up required
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Built and reviewed by Luvero Accounting
- Reviewed by Dan Edwards FMAAT
- AAT licensed accountancy practice, Bawtry, South Yorkshire
- Tax rates last reviewed 16/09/2026
- How the calculators work
What this calculator works out
It takes your company's taxable profit for one accounting period and works out the Corporation Tax due on it, which of the three bands the profit falls in, what marginal relief is worth, and the effective rate you end up paying. It uses the rates for the financial year starting 1 April 2026, which are unchanged from the year before.
How Corporation Tax works in 2026/27
There are two rates. Profits up to the lower limit of £50,000 are taxed at the small profits rate of 19 per cent. Profits at or above the upper limit of £250,000 are taxed at the main rate of 25 per cent on the whole amount. In between, the main rate applies to the whole profit and is then reduced by marginal relief, which is why the effective rate climbs gradually from 19 to 25 per cent rather than jumping.
Marginal relief is 3/200 of the difference between the upper limit and your profit. Inside the band every extra £1 of profit is taxed at 26.5 per cent, higher than the main rate itself. That is worth knowing before you decide the timing of income, a pension contribution or a year-end purchase.
If you control more than one company, the limits are shared between them. Two associated companies means the small profits rate stops at £25,000 each rather than £50,000, and the marginal relief band runs from £25,000 to £125,000. A period shorter than 12 months reduces the limits in proportion to its length.
Worked example: £100,000 taxable company profit
One company, a full 12 month accounting period, 2026/27 rates. The profit sits inside the marginal relief band, so the main rate applies and relief is then deducted.
| Taxable profit | £100,000 |
|---|---|
| Small profits threshold | £50,000 |
| Main rate threshold | £250,000 |
| Main rate on the whole profit, 25% | £25,000 |
| Marginal relief: (£250,000 less £100,000) × 3/200 | -£2,250 |
| Corporation Tax due | £22,750 |
| Effective Corporation Tax rate | 22.75% |
| Profit remaining after Corporation Tax | £77,250 |
The effective rate is neither 19 nor 25 per cent because the first £50,000 is effectively taxed at 19 per cent and the next £50,000 at 26.5 per cent. Averaged across the whole £100,000 that comes to 22.75 per cent. Push the profit to £101,000 and the tax rises by £265, not £250, because each extra pound inside the band also removes 1.5p of relief.
Corporation Tax questions
What is the Corporation Tax rate for 2026/27?
For the financial year starting 1 April 2026 the small profits rate is 19 per cent on taxable profits of £50,000 or less, and the main rate is 25 per cent on profits of £250,000 or more. Between the two limits the main rate applies with marginal relief. Both rates and both limits are unchanged from the financial years starting 1 April 2024 and 1 April 2025.
The limits apply to one company with a 12 month accounting period. They are divided by the number of associated companies and reduced for a shorter period.
What is Corporation Tax marginal relief?
Marginal relief is a deduction from the Corporation Tax bill for a company whose profits fall between the £50,000 lower limit and the £250,000 upper limit. Without it the rate would jump from 19 to 25 per cent the moment profits passed £50,000. With it the effective rate rises gradually.
The standard formula is 3/200 of the amount by which the upper limit exceeds your profit. On a profit of £100,000 that is (£250,000 less £100,000) × 3/200, which is £2,250. The relief is deducted from tax at the main rate. Where a company receives dividends from companies outside its group the calculation uses augmented profits, which this calculator does not model.
Why is the marginal Corporation Tax rate 26.5%?
Inside the marginal relief band each additional £1 of profit is taxed at the 25 per cent main rate and also reduces marginal relief by 3/200 of £1, which is 1.5p. Add the two together and each extra pound costs 26.5p in tax. That is why the tax on the next £1,000 of profit shown by this calculator is £265 for any profit between £50,000 and £250,000.
Once profits pass £250,000 the relief has run out, so the marginal rate drops back to 25 per cent. Below £50,000 it is 19 per cent.
What is an associated company?
Two companies are associated if one controls the other, or the same person or group of persons controls both. Control usually means holding more than half the shares or voting rights, or being entitled to more than half the assets on a winding up. A company counts if it was associated at any point during the accounting period, wherever in the world it is based.
Dormant companies are left out. So, in most cases, are companies whose only activity is holding shares in their subsidiaries. Companies controlled by your spouse, civil partner or other close relatives are only counted where there is substantial commercial interdependence between the businesses. HMRC's Company Taxation Manual sets out the detail, and it is one of the areas where an accountant should confirm the count before you rely on it.
Does the £50,000 Corporation Tax threshold change if I own more than one company?
Yes. Both the £50,000 lower limit and the £250,000 upper limit are divided by the number of associated companies, counting the company itself. With two associated companies each has a lower limit of £25,000 and an upper limit of £125,000. With three the limits are £16,667 and £83,333.
The divided limits are used in the marginal relief formula too, so a profit of £100,000 in one of two associated companies is taxed at £25,000 less relief of (£125,000 less £100,000) × 3/200, which is £375, leaving £24,625. Change the associated companies box above to see this.
What happens if my accounting period is shorter than 12 months?
The lower and upper limits are reduced in proportion to the length of the period. A period of 181 days, roughly six months, has a lower limit of £24,795 and an upper limit of £123,973 for one company. A profit of £100,000 over that period therefore falls much further into the marginal relief band than the same profit over a full year, and the tax is £24,640 rather than £22,750.
Short periods are common in a company's first year and when a year end is changed. An accounting period cannot be longer than 12 months for Corporation Tax: a longer set of accounts is split into one period of 12 months and a second for the remainder, each with its own computation. Choose "Shorter than 12 months" above and enter the dates to see the effect.
When does a limited company pay Corporation Tax?
For most companies the tax is due nine months and one day after the end of the accounting period. A company with a 31 March 2027 year end pays by 1 January 2028. The Company Tax Return itself is due 12 months after the period end, so the payment deadline comes first. HMRC charges interest on anything paid late.
Companies with taxable profits over £1.5 million, a limit which is also divided by the number of associated companies, pay in quarterly instalments starting during the accounting period rather than in one sum afterwards.