Email hello@jukkablomberg.com. Tell us your device, the app version (shown on the app’s About screen) and the calculator you were using. We answer in English.
A result looks wrong
Send the calculator name, the values you entered and the number you expected. Every calculator on this site states its assumptions — several ignore air resistance or assume ideal conditions, which is the usual reason a real-world figure differs. Corrections to the physics are welcome and we act on them.
Does it work offline?
Yes. The app makes no network requests at all. If a calculator does not load, reopening the app is the fix; nothing is being downloaded.
Deleting your data
The app stores only your recent calculators and your unit preference, on your device. Clearing the app’s storage in your phone settings, or uninstalling it, erases both immediately. There is no account to delete and no server copy, as the privacy page explains.
The web version
Every calculator in the app is also free on usephysics.com. Published by UsePhysics (usephysics.com), Helsinki, Finland.