Capital allowances: what are they and do they affect my estimate?

A plain-English explanation of capital allowances and why this calculator stays high-level, using profit as the input.

Capital allowances can affect taxable profit, but rules can be detailed.
This calculator stays high-level and uses profit as the input to reduce maintenance risk.
If capital allowances apply, treat the estimate as planning and verify official guidance.

What capital allowances are

Capital allowances are a way tax rules may let you get relief for certain purchases. Details depend on asset type and conditions.

How to use this tool

If you have already accounted for the correct treatment in your profit figure, enter that profit. If you have not, the estimate may not match your final filing.

Common mistakes

Treating capital allowances as a simple expense rule in all cases, or ignoring the tax year you are filing for.

Not tax advice. This page is an educational guide. For official rules, verify the sources below.

Open self-employed calculator How this is maintained

Last updated: 2026-04-20

FAQ

Will the calculator compute capital allowances for me?

No. It expects a profit input.

Can I still use the calculator?

Yes, for planning, but verify the final figure using official guidance.

Where is the official reference?

See the GOV.UK capital allowances guidance.

Sources

For official rules and definitions, verify with the references below.

https://www.gov.uk/capital-allowances