Terms of service

Tachyon is adaptive SAT practice: original questions, named-mistake diagnosis, drills, lessons, and full-length practice tests. It's an educational tool, not a school, a tutor-of-record, or a guarantee.

Every account starts on the free tier — daily adaptive practice, named mistakes, and lessons, no card required. Paid plans unlock unlimited practice and full-length tests. Tachyon is in early access: features may change, break, or be rebuilt — that's what early access means.

You must be at least 13 to create an account, and if you're under 18 you need a parent or guardian's permission.

Give us accurate info, keep your password to yourself, and use one account per person. You're responsible for what happens under your login.

We can suspend or close accounts that abuse the service (see acceptable use below). You can delete your account any time by emailing us.

The free tier is real and ongoing: daily adaptive practice, your error report, and lessons, with no card ever required for it. We will never charge you without your explicit consent — upgrading is always an action you take, never something that happens to you.

Paid plans are published on the pricing page. Signing up during early access locks the founder rate we advertise ($19/mo for life on Pro) — the lock is a promise about the price you'd pay if you upgrade, not a charge. Subscriptions can be canceled any time and run through the period already paid.

Don't scrape, copy, resell, or redistribute the question bank or any part of it. The questions, explanations, mistake taxonomy, and lessons are Tachyon's original work and are licensed to you for your own test prep only.

Don't share accounts, probe or disrupt the service, or use Tachyon to build a competing question bank.

Tutors may only connect student accounts they actually work with, with the student's knowledge.

Your practice data is yours. How we collect and use it is covered by the privacy policy, which is part of these terms.

We work hard on calibration, but practice scores are estimates and no score improvement is promised. The SAT is administered by the College Board; Tachyon is not affiliated with or endorsed by the College Board, and our practice tests are not official.

Tachyon is provided “as is.” To the fullest extent the law allows, we disclaim implied warranties, and our total liability to you is limited to the amount you've paid us in the past 12 months.

We may update these terms; material changes get announced on this page with a new date. Continuing to use Tachyon after a change means you accept it.

Questions about these terms, your data, or your account: email us at the address below.