Caliper: Vernier Trainer

Learn to read a metric vernier caliper with an interactive instrument. See where the moving zero sits, practise each new step, and build confidence before using a real caliper.

START WITH THE BASICS A short interactive introduction shows how the caliper measures and guides your first whole-millimetre reading. Level 1 gives you five free exercises with feedback.

KEEP LEARNING The guided course has 30 levels. Start with whole millimetres, then learn half-millimetre readings and finer 0.02 mm vernier steps. Checkpoints show your accuracy and time so you can improve.

PRACTISE YOUR WAY Read measurements, set the jaws to a target, or try timed Speed challenges. Zoom and move the scale to inspect the markings.

ONE PURCHASE FOR FULL ACCESS The introduction and Level 1 are free. A single non-consumable in-app purchase unlocks Levels 2–30 and the Read, Set and Speed modes. No subscription or account is required. Restore Purchases is available in the app.

Caliper is a training simulator; it does not measure physical objects with your phone.

Discovery signals