Terms of Use

Privacy & Security

Your financial data is sensitive. Here’s exactly what happens to it — and what doesn’t.

How Your Data Flows

Your broker file travels over an encrypted connection to our server, where it is processed entirely in memory — never written to disk or saved to any database.

When you upload a broker CSV, four things happen — all in memory on our server:

1. Your file is received — the CSV is parsed in memory. It is never written to disk.
2. Exchange rates are applied — HMRC’s official monthly rates convert foreign-currency trades to GBP.
3. The engine calculates your report — all matching rules, option strategies, corporate actions, and income calculations run in memory.
4. You see the result — the finished report is sent back to your browser and rendered on screen. You can download it as a PDF, and nothing is kept afterwards.

Data Storage by Tier

On every plan, your CSV is sent to our server for calculation, processed in memory only, and never stored.

When a report is saved to your reports list, the statements it was built from are kept in your browser’s own storage beside it, so a statement you add later on the Edit page is read together with them. They stay on your device, are never sent anywhere the report itself is not, and are deleted with the report.

Firms that cannot send client files to a third party at all can have a dedicated deployment on the Business plan, where the engine runs in the browser and files never reach us — see Private Instance.

The taxpayer name, UTR and broker you can put on a report (see Your Name and UTR on the PDF) never leave your browser at all. They are kept there, on the one report they belong to: they are not part of any calculation request, they are in no analytics event, and they are never logged. The PDF and the CSV are both built on your own device, so putting your name on either sends us nothing. The tax engine never sees them, so they cannot change a single figure — they are labels on a document.

Because they belong to that one report, there is deliberately no “remember this for next time” setting anywhere in the product: filling them in for one client can never pre-fill or leak them onto another client’s report. Clearing the section removes all three at once, and deleting the report from Recent deletes them with it. And because your browser is where they live, they are on that device only — a different browser, or one whose data you have cleared, has no copy.

Analytics & Cookies

We use Vercel Web Analytics to understand how many people visit the site. It collects page views and country-level geography — no personal data, no IP addresses, no fingerprinting. It is privacy-compliant by design and does not use cookies for tracking.

We do not use Google Analytics, Facebook Pixel, or any advertising tracker.

What We Don’t Do

• We do not sell or trade your data, and we do not share it with advertisers or data brokers
• We do not store your broker files, transaction history, or calculated reports
• We do not receive the taxpayer name, UTR or broker on your report — they stay in your browser
• We do not use advertising cookies or tracking pixels
• We do not fingerprint your browser or device

If You Sign In

Sign-in is only needed for paid tiers. If you sign in with Google, two pieces of information end up on file:

• Your email and display name, taken from the Google sign-in token
• An internal account ID, the date you signed up, and the date you last logged in

That is the entire record, and none of it is linked to your trades or reports.

The legal basis is contract performance (Article 6(1)(b) of the UK GDPR): we need this much to run the account.

Who Else Touches Your Data

A short list of services involved in running the site:

• Supabase — holds the sign-in record (EU region, encrypted at rest and in transit)
• Google — runs the OAuth sign-in itself (US, transfers covered by Standard Contractual Clauses)
• Vercel — hosts the site and runs the cookieless analytics described above

If we add or change any of these, this page is updated.

How Long Things Are Kept

The sign-in record lives as long as the account does. Ask us to delete the account and it goes too. Supabase keeps short-term backups for service recovery, typically a few days.

If you have never signed in, there is no record of you to keep or delete.

Your Rights

Under UK and EU data protection law you can ask us to:

• Show you what we have on file (it’s only what’s listed under “If You Sign In”)
• Correct anything that’s wrong
• Delete the account and the record with it
• Send you a copy as a JSON export
• Stop processing it

Email support@cgtcalculator.io and say what you need. Mention the email address you signed in with so we can find the record. We reply within 30 days under the GDPR clock, usually much sooner. There is no form to fill in.

If you think we mishandled your data, you can also complain to the UK Information Commissioner’s Office at ico.org.uk.

See also our privacy article for the technical details.

Google User Data

If you choose to sign in with Google, the following applies to how we handle your Google user data.

Data Accessed

We use Google Identity Services solely for authentication. When you sign in with Google, we receive a limited ID token containing:

• Your email address
• Your display name (if provided by your Google account)

We do not request access to any other Google services such as Google Drive, Google Sheets, Gmail, or any other Google API.

Data Usage

Your Google user data is used exclusively to:

• Authenticate your identity and create a user session
• Display your name or email in the application header so you can confirm you are signed in

Your Google user data is not used for advertising, analytics, profiling, or any purpose other than authentication.

Data Sharing

Your Google ID token is passed to our authentication provider, Supabase, to verify your identity and manage your session. Apart from Supabase, we do not share your Google user data with any other third parties.

Data Storage & Protection

Your email address and display name are stored securely within Supabase’s authentication system, which provides encryption at rest and in transit. No Google user data is stored in local files, cookies, or any other location beyond the authenticated session.

All communication between your browser, Google, and our authentication provider occurs over HTTPS.

Data Retention & Deletion

Your Google authentication data is retained only for as long as your account exists. You may request deletion of your data at any time by contacting us at our contact page. Upon receiving a deletion request, we will remove all data associated with your account from our authentication system.

You can also revoke CGT Calculator’s access to your Google account at any time through your Google Account permissions page.

Plans & Pricing

We offer a free plan (Museum) and two paid plans: Investor (shown on the site as “Fish & Chips”) and Business (“High Tea”). The free plan lets you calculate a limited number of disposals. The paid plans unlock unlimited disposals, the full per-trade report, PDF export, options and fund (ERI) reporting.

Private in-browser processing is available on the Business plan by request — see Private Instance. Where we agree to provide one, the instance is set up for a period agreed with you and may be renewed by agreement. It is not a permanent part of the Business plan, and we may retire the deployment at the end of the agreed period.

Each paid plan includes a set number of report generations per subscription period, with a higher allowance on the Business plan; Business subscribers can also buy one-time top-up packs when they need more. Editing or recalculating a report you have already generated does not use up your allowance.

The paid plans are annual subscriptions. The price of each is the amount shown on our pricing page and confirmed at checkout before you pay; prices are in pounds sterling (GBP) and include VAT where it applies.

An active paid subscription unlocks every tax year — past and future — for as long as the subscription remains active.

Subscriptions, Billing & Renewal

Payments are processed by Stripe. We do not see or store your full card details; they are handled by Stripe under their own terms.

Your subscription renews automatically each year. Unless you cancel beforehand, we will charge your payment method so your access continues without interruption.

If we ever change the renewal price, we will tell you by email in advance, and you can cancel before the new price takes effect. Renewals are charged at the price we last notified to you.

You can cancel at any time from the Subscription tab in your account. When you cancel, your access continues until the end of the period you have already paid for and is not renewed after that.

If a renewal payment fails after Stripe’s automatic retries, your plan reverts to the free tier until payment succeeds.

Cancellation & Refunds

You have 14 days from purchase to cancel for a full refund (a “cooling-off period”) — wherever in the world you are. UK and EU consumers also have this right by law under the Consumer Contracts Regulations 2013; if your local law gives you more, that applies too.

The paid plan unlocks your full report straight away. By subscribing you ask us to start your subscription and make the report available immediately, and you agree that the 14-day cooling-off refund applies only while you have not yet used the paid report. To try the tool first, run your import on the free plan before you pay.

None of this affects your rights if the paid report is faulty or doesn’t work. If your file fails to parse, or the report comes out wrong, you’re entitled to have it fixed or to a refund regardless of the cooling-off period — just tell us and send us the file (use “Send report” in the error message) so we can check.

Your Licence

A paid subscription is a single licence tied to the individual who holds the account. What you may do with it depends on your plan — the Investor plan is for working out your own tax, while the Business plan is licensed for professional use.

Investor (“Fish & Chips”) is a personal licence. It is sold for working out your own UK Capital Gains Tax — not as a tool for doing other people’s tax. It does not permit preparing or processing the tax affairs of clients or other taxpayers, nor bulk, agency, bureau or other commercial use. If you prepare returns on behalf of others, you need the Business plan.

Business (“High Tea”) is a professional licence. It is designed for accountants, tax advisers and others who prepare UK Capital Gains Tax reports on behalf of clients and other taxpayers, and it permits that use — within your plan’s report allowance, with top-up packs available when you need more. Delivering a report to the client it was prepared for is part of that use and is allowed.

We don’t monitor what you calculate. Your files are never stored, so this licence runs on trust — and in return we ask you to keep to it. On either plan, your subscription does not permit:

• sharing your account or sign-in details with anyone else, or letting others use your subscription;
• reselling, sublicensing, white-labelling or redistributing the service or the calculator itself as your own product.

Not sure which plan fits, or need cover for a larger practice? Contact us at support@cgtcalculator.io and we’ll be glad to help.

If it becomes clear that a subscription is being used outside these terms — for example, processing clients’ data on a personal Investor plan, sharing an account, or reselling the service — we will ask you to stop and to move to the right plan. Where there is genuine misuse, we may suspend or end the subscription; if we end it for any other reason, we will refund the unused part of what you paid.

Acceptable Use

You agree not to misuse the service. In particular, you must not try to bypass or tamper with the plan or paywall controls, reverse engineer, decompile or extract the calculation engine, access paid features without a paid plan, or use the service unlawfully or in any way that harms it or other users.

Disclaimer

This calculator is provided for general information only and is not professional tax advice. We do not warrant that the results are accurate, complete or fit for filing, and you must check the figures before relying on them.

Always consult a qualified tax professional for advice on your situation. You remain responsible for what you submit to HMRC.

Limitation of Liability

We do not exclude or limit our liability where it would be unlawful to do so — including for death or personal injury caused by our negligence, or for fraud. This does not affect your statutory rights as a consumer.

Subject to that, the service is provided “as is”. We are not liable for loss arising from figures you enter incorrectly, or from relying on the results without checking them or taking professional advice, nor for indirect or consequential loss. Our total liability to you for any claim is limited to the greater of the fees you paid us in the 12 months before the claim and £100.

Service Availability

We aim to keep the service available but do not guarantee that it will be uninterrupted or error-free, and we may change, suspend or withdraw features. We are not responsible for delays or failures caused by events outside our reasonable control.

Changes to These Terms

We may update these terms from time to time. If a change materially affects a paid subscriber, we will give reasonable notice by email before it takes effect, and you may cancel before then if you do not agree. The version in force is the one published on this page on the date shown above.

General

If any part of these terms is found to be unenforceable, the rest continues to apply. A delay in enforcing these terms is not a waiver of our rights. We may transfer our rights and obligations under these terms to another organisation, but this will not affect your rights. Together with the items we link to (such as our privacy information), these terms are the entire agreement between you and us for the service.

Governing Law

These terms are governed by the laws of England and Wales, and disputes are subject to the courts of England and Wales. If you are a consumer, you keep the benefit of any mandatory consumer-protection rules of your country of residence and may be able to bring proceedings there.

Acceptance

By using this calculator, or by agreeing to these terms at checkout and subscribing to a paid plan, you accept these terms.