Privacy Policy

This Privacy Policy explains how Percentage Change Calculator UK ("we", "us", "the Operator") collects, uses, stores and protects personal data when you visit our website at percentagechangecalculator.co.uk (the "Service").

We are committed to protecting your privacy and complying with the UK General Data Protection Regulation (UK GDPR), the Data Protection Act 2018, and the Privacy and Electronic Communications Regulations 2003 (PECR).

The data controller responsible for your personal data is the Operator of the Service. For any privacy-related questions, please contact us using the details in Section 13.

We aim to collect the minimum amount of personal data needed to operate the Service, respond to enquiries and comply with the law. The categories of information we may collect are summarised below.

We use the limited information we collect for the following specific purposes:

• Operating the Service: Loading pages, processing requests and displaying calculation results in your browser.
• Analytics & Improvement: Understanding which pages are visited, how users find us, and where the user experience can be improved.
• Responding to Enquiries: Replying to messages submitted via the contact form or sent to our email inbox.
• Security & Abuse Prevention: Detecting, preventing and investigating fraudulent, abusive or unlawful use of the Service.
• Legal Compliance: Meeting our obligations under UK law, including record-keeping and responding to lawful requests from authorities.
• Communication: Sending you a direct reply if you have asked us a question — we do not send marketing emails unless you have separately and explicitly opted in.

The Service uses cookies and similar technologies (such as local storage) to remember preferences, measure traffic and improve user experience. Cookies are small text files stored on your device when you visit a website.

We use the following categories of cookies:

• Essential cookies — required for the website to function correctly (e.g. remembering your cookie consent preference). These cannot be disabled.
• Analytics cookies — help us understand how visitors use the site so we can improve it. We use Google Analytics for this purpose.
• Preference cookies — remember choices such as theme or recently used values (stored locally in your browser only).

We use a small number of trusted third-party services to operate and improve the Service. Each third-party processor has its own privacy policy governing how they handle your data:

• Google Analytics — web analytics to understand page views, traffic sources and user behaviour. Google's Privacy Policy.
• Google AdSense — if we display ads, Google may use cookies to serve relevant ads. You can opt out of personalised ads via Google Ads Settings.
• Cloudflare / CDN provider — for caching and security, may log IP addresses and request metadata for abuse prevention.
• Google (Gmail) — used for handling email correspondence sent to percentagechangecalculator@gmail.com.
• Reddit, Facebook, Discord — if you click a social link, you'll be taken to a third-party platform governed by its own privacy policy.

We do not share, sell or rent your personal data to any other third party for marketing purposes.

We take reasonable technical and organisational measures to protect any personal data we hold. These include:

• HTTPS / TLS encryption for all data transmitted between your browser and our server.
• Access controls limiting who at the Operator can view correspondence or analytics data.
• Regular security reviews of third-party tools and dependencies.
• Browser-side processing of calculation inputs so that sensitive numbers never traverse our network.

No method of transmission or storage is 100% secure. While we strive to protect your data, we cannot guarantee absolute security.

We retain personal data only for as long as is necessary for the purposes set out in this policy, or as required by law:

• Analytics data: Aggregated, anonymised data may be retained for up to 14 months, after which it is automatically deleted or further anonymised.
• Contact form submissions & email correspondence: Retained for up to 2 years from the date of last correspondence, to allow follow-up and to maintain evidence of enquiry handling.
• Server access logs: Retained for up to 90 days for security and abuse-prevention purposes.
• Calculation inputs: Not retained at all — they are not transmitted to or stored on our servers.

When the retention period expires, personal data is securely deleted or irreversibly anonymised.

Under the UK GDPR and Data Protection Act 2018, you have the following rights regarding your personal data:

To exercise any of these rights, please contact us using the details in Section 13. We will respond within one calendar month of receiving your request, as required by UK GDPR.

The Service is designed to be a general-purpose educational maths tool and is not directed specifically at children under the age of 13. However, we understand that students of all ages may use the calculator as part of their studies.

We do not knowingly collect personal data from children under 13. If you are a parent or guardian and believe we have collected data from your child, please contact us immediately using the details in Section 13 and we will promptly delete that information.

The Operator is based in the United Kingdom. However, some of the third-party services we use — such as Google Analytics, Google AdSense and our CDN provider — may process data outside the UK.

Where this occurs, we rely on the legal mechanisms approved by the UK government, including International Data Transfer Agreements (IDTAs) and the UK adequacy regulations for countries deemed to provide adequate protection.

If you would like a copy of the safeguards we rely on, please contact us using the details in Section 13.

Our Service contains links to our official profiles on third-party platforms:

• Reddit: u/Percentage_changecal
• Facebook: Percentage Change Calculator
• Discord: @PercentageChange

These platforms have their own privacy policies and we encourage you to read them. We are not responsible for how third-party social platforms handle your data once you leave our website.

We may update this Privacy Policy from time to time to reflect changes in our practices, technology, legal requirements or for other operational reasons.

When we do, we will revise the "Last updated" date at the top of this page. We encourage you to review this policy periodically.

If we make a material change — for example, a new category of data collection or a new third-party processor — we will provide a more prominent notice (such as on the homepage or via a cookie banner) at least 30 days before the change takes effect, where reasonably possible.

If you have any questions, concerns, or requests relating to your personal data — or if you wish to exercise any of your rights under UK GDPR — please contact us using the details below: