Capital Allowances Calculator

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

Period & purchases

Period start

Period end

Taxable profit before capital allowances (£)

GBP

Assets bought in the period

Cost (£)

CO2 (g/km)

Second-hand

Corporation Tax saved this year

£7,102.00

Tax falls from £28,050 to £20,948

Allowances this year

£26,800.00

On £55,000 spent

Carried forward

£28,200.00

Written down in later years

Allowance by asset

Treatment	Cost	Allowance	Carried forward
Full expensing (100%)	25,000.00	25,000.00	0.00
Special rate pool writing-down allowance	30,000.00	1,800.00	28,200.00
Total	55,000.00	26,800.00	28,200.00

Estimate only. For a company with no opening pool balances, treating each asset as bought at the end of the period. Each row shows the asset on its own; the total applies the £1 million Annual Investment Allowance across all of them. Cars cannot get full expensing or the Annual Investment Allowance.

Guidance only. This calculator gives a general estimate and is not tax advice. Speak to your accountant before relying on these figures or making any decisions based on them.

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).

Need to file the CT600?

This calculator is for guidance only. Tax Optimiser prepares the full corporation tax computation and files the CT600 and accounts with HMRC and Companies House.