# Capital Allowances Calculator

> Calculate capital allowances for a UK company: full expensing, the Annual Investment Allowance, cars by CO2 emissions and the Corporation Tax saved.

Add the equipment, fixtures or cars your company has bought to see the allowances for the year and the Corporation Tax they save.

Use the calculator: https://www.taxoptimiser.co.uk/calculators/capital-allowances

Example: A company with a profit of £120,000 in the year to 31 March 2027 that buys £25,000 of new equipment and a £30,000 car with CO2 emissions of 120g/km can claim £26,800.00 of capital allowances for the year, saving £7,102.00 of Corporation Tax. The other £28,200.00 is carried forward.

## Full expensing and the Annual Investment Allowance

Companies can deduct 100% of the cost of new main-rate plant and machinery in the year of purchase under full expensing. The Annual Investment Allowance gives the same 100% deduction on up to £1 million a year of most plant and machinery, including second-hand assets. New special-rate assets, such as integral features of a building, get a 50% first-year allowance instead.

## Cars

Cars do not qualify for full expensing or the Annual Investment Allowance. A new zero-emission car gets a 100% first-year allowance. Other cars go into the main pool if their CO2 emissions are 50g/km or less, or the special rate pool at 6% a year if they are higher.

## What is carried forward

Cost not relieved in the first year stays in a pool and is written down each year: 6% for the special rate pool, and 14% for the main pool from 1 April 2026 (18% before).

## Dates and limits to watch

The 100% first-year allowance for new zero-emission cars ends on 31 March 2027; a car bought after that goes into the main pool. An accounting period that spans 1 April 2026 uses a hybrid main pool rate, between 18% and 14%, weighted by the days falling either side. The £1 million Annual Investment Allowance is reduced in proportion for a period shorter than 12 months, and a group of companies, or companies under common control, share a single allowance between them. The calculator applies the first three of these. It does not share the Annual Investment Allowance, so it assumes the whole allowance belongs to your company.

## Frequently asked questions

### What is full expensing?

A 100% first-year allowance for companies on new main-rate plant and machinery, so the whole cost is deducted from profit in the year of purchase. It is not available on cars or second-hand assets.

### What is the Annual Investment Allowance limit?

£1 million a year. It gives a 100% deduction on most plant and machinery, including second-hand assets, but not cars.

### Can a company claim capital allowances on a car?

Yes, but not full expensing or the Annual Investment Allowance. A new zero-emission car gets a 100% first-year allowance. Other cars are written down in the main pool if their CO2 emissions are 50g/km or less, or in the special rate pool at 6% a year if higher.

## Related calculators

- [Corporation Tax Calculator](https://www.taxoptimiser.co.uk/calculators/corporation-tax.md): Estimate Corporation Tax for a UK limited company with marginal relief.
- [Loss Carry-Back Calculator](https://www.taxoptimiser.co.uk/calculators/loss-carry-back.md): Repayment from carrying a trading loss back, compared with carrying it forward.
- [Corporation Tax Deadlines Calculator](https://www.taxoptimiser.co.uk/calculators/corporation-tax-deadlines.md): Payment, CT600 and Companies House dates for any accounting period.

## Sources

- [Claim capital allowances](https://www.gov.uk/capital-allowances) (GOV.UK)
- [Annual Investment Allowance](https://www.gov.uk/capital-allowances/annual-investment-allowance) (GOV.UK)
- [Capital allowances on business cars](https://www.gov.uk/capital-allowances/business-cars) (GOV.UK)

---
Last updated 11 October 2026. Guidance only: a general estimate, not tax advice. Published by Tax Optimiser, UK tax filing software (https://www.taxoptimiser.co.uk).