Terms, in plain words.

Last updated 20 August 2026. Operated from the United Kingdom, full company details will appear here when gains.tax's registration completes.

What gains.tax is

A calculator that runs on your device. It applies published UK tax rules to data you give it and shows its working, including the HMRC manual paragraphs it relied on. It is information, not tax advice, and it does not know your wider circumstances. You are responsible for what you file. If your affairs are complicated, involve a professional.

Your data, your machine, your backups

Because your data never reaches us, we cannot recover it for you. Use the app's session export and keep your own backups. We are not liable for data lost from your own device or browser storage.

The free tier and the account fee

Up to 1,000 transactions the app is free, including report downloads. The account fee covers 1,000 to 9,999 transactions and all tax years, past and future, for the person who bought it. It is a one-time payment, not a subscription. Keys are for your own use on your own devices.

Accuracy

We work to keep the engine correct against published HMRC guidance and cite what it does. Software has bugs, source data has gaps, and the output is only as good as the data you import. Check your reports before filing, the app is built to make checking easy.

Acceptable use

Do not use the app or the relay to break the law, to abuse exchanges' APIs, or to attempt to disrupt the service. The professional directory's contact details are for engaging professionals, not for scraping or marketing.

The legal lines

The service is provided as is, and to the extent the law allows, liability is limited to the amount you paid us, which for most users is nothing. These terms are governed by the law of England and Wales. Nothing in them limits liability that cannot lawfully be limited.