Without internet
Use CTRI offline
Keep a whole book on your phone. You can read it, and practise its questions, with no internet and no data. When you are online again, we quietly bring your copy up to date, downloading only what changed.
Put CTRI on your home screen
It opens like an app, even without internet.
On an iPhone or iPad: open this page in Safari, tap the Share button, then “Add to Home Screen”.
Your books
- Loading the list of books…
Good to know
- A saved book includes its chapters, pictures, equations and practice questions. PDFs and search are not included: search needs internet.
- What you mark in practice mode (“I got it”, “Try again later”, your working) stays on your phone and is never sent to us.
- Phones can clear saved data if they run short of space. On an iPhone, Safari may clear it if you do not open CTRI for several weeks. If a book disappears, save it again here.
- Saving a book uses mobile data once. On Wi-Fi it costs you nothing.