Privacy Policy
This policy explains what personal data PracticeCalculus collects when you use PracticeCalculus (the website, lessons, practice tools and emails), why we collect it, who we share it with and the choices you have. We keep it short and specific: we only collect what we need to run the service, and we never sell your data.
If you have a question about your data, email us at [email protected].
What we collect
When you create an account
- Your name and email address.
- Your password, which we store only as a secure one-way hash. We cannot see it.
- Your language, time zone and daily goal, so lessons, reminders and streaks match your day.
- Your email preferences.
When you learn and practice
- Your answers, lesson attempts, mistakes, XP, streaks and progress through each course. This is what makes features like mistake review, streaks and progress tracking work.
- If you start learning without an account, your progress is kept in your browser session. If you then sign up, it is moved into your new account.
When you subscribe to Pro
- Your plan, subscription status, trial and renewal dates. Payments are handled by our payment provider, Bachs. We never see or store your full card number.
When you contact us
- Your message and email address, so we can reply.
Technical data
- Like every website, our servers process your IP address and basic request details (browser, pages requested, time) to deliver pages, keep the service secure and fix errors. Server logs are kept for a limited time.
Cookies
We use a small number of cookies:
| Cookie | Purpose | Type |
|---|---|---|
| Session cookie | Keeps you signed in and remembers guest progress during a visit | Necessary |
| XSRF-TOKEN | Protects forms against cross-site request forgery | Necessary |
| Remember me | Keeps you signed in if you choose "Remember me" | Necessary |
| appearance | Remembers light or dark mode | Preference |
| locale | Remembers your language | Preference |
| cookie_consent | Remembers your cookie choice | Necessary |
Google Analytics (_ga, _ga_*) |
Helps us understand how the site is used | Analytics, only with your consent |
Google Analytics cookies are only set if you click Accept in the cookie banner. You can change your choice at any time with the Cookie settings link at the bottom of the page.
How we use your data
- To run your account and show your lessons, progress, streaks and practice.
- To check your answers and give feedback.
- To manage your subscription and billing.
- To send account emails, such as email verification, password resets and billing notices. These are needed to run your account.
- To send learning emails, such as streak reminders, weekly progress summaries, milestone notes and a reminder if you have not practiced for a while. You can turn each of these off in Settings, Email, or with the unsubscribe link in any of these emails.
- With your consent, to measure how the site is used so we can improve it.
- To keep the service secure and prevent abuse.
Legal bases (EEA and UK users)
We process your data because it is needed to provide the service you signed up for (contract), because you agreed to it (consent, for analytics cookies and learning emails, which you can withdraw at any time), and for our legitimate interests in keeping the service secure and improving it.
Who we share data with
We use trusted service providers who process data only on our instructions:
- DigitalOcean: hosts our servers and database.
- Cloudflare: delivers the website securely and quickly, and routes email sent to our domain.
- Mailgun: sends our emails.
- Bachs: processes subscription payments.
- Google Analytics: measures site usage, only if you accept analytics cookies.
We use AI models to help write and translate our public learning content. Your personal data and your answers are not sent to AI providers for this.
We may disclose data if the law requires it. We do not sell your personal data or share it for advertising.
Some of these providers are located outside your country, including in the United States. Where required, transfers are protected by appropriate safeguards such as standard contractual clauses.
How long we keep data
We keep your account data for as long as your account exists. When you delete your account in Settings, Profile, your account, progress, attempts, XP and subscription records are deleted from our database. Some records may remain for a short time in backups, and we keep billing records for as long as the law requires.
Your rights
Depending on where you live, you can ask to access, correct, export or delete your data, object to or restrict how we use it, and withdraw consent. You can change most things yourself in Settings. For anything else, email [email protected]. You also have the right to complain to your local data protection authority.
Children
PracticeCalculus is meant for students aged 13 and older. If you are under the age required by the law in your country to agree to this policy yourself, a parent or guardian must agree for you. If you believe a child has given us data without permission, contact us and we will delete it.
Changes
We will update this page if our practices change and show the new date below. If the changes are significant, we will tell you by email or on the site.
Last updated: November 4, 2026