Ruler — Screen Measure Tool

Your phone is in your pocket, but your ruler is somewhere else?

Ruler turns your phone screen into a practical measuring tool. Measure lengths, distances, angles and object sizes directly on your screen.

Check whether a shelf will fit, or find out how long a small part is. Open the app, calibrate it and start measuring.

📏 CALIBRATE ONCE, MEASURE WITH CONFIDENCE

Every phone screen has a different size and pixel density. That is why Ruler lets you match the on-screen scale to a real measurement.

Calibrate the app with a bank card or with a physical ruler you already own. After calibration the readings on screen match your device.

Saved measurements show their calibration status as well, so you always know how a reading was taken.

📐 6 MEASURING MODES

Length
Measure a distance in a single reading that starts at the left edge of the screen.

Range
Measure the distance between two handles and see both positions at once.

Rectangle
Measure the width and the height of an object together.

Two points
Measure the distance between any two points on the screen. Δx, Δy and the slope are shown as well.

Protractor
Measure the angle between two arms. Work on a 90°, 180° or 360° dial.

Long ruler
Measure objects that do not fit on the screen. Move the ruler along the object and keep measuring.

🔒 YOUR DATA STAYS YOURS

Ruler keeps measuring as simple as it can be. You do not need an account and it asks for no unnecessary permissions. There are no ads while you measure: an ad appears only if you choose to watch one to unlock a Pro feature for 1 hour. Apart from that, the only thing that leaves your device is an anonymous crash report, and only if the app fails — sent so we can find and fix the problem.

Open it, measure, get on with your work.

💾 SAVE YOUR MEASUREMENTS

Save your measurements, name them and open them again later. Tap a saved measurement and the reading returns to the ruler.

Export everything as CSV and use it in Excel and Google Sheets.

🎯 TOOLS FOR CAREFUL MEASURING

Use fine step to measure with more control. Lock the reading and the value stays put while you move the phone. Precise reading shows up to two decimal places.

The first time you open the app, a short tour walks you through the tools; you can start it again any time from Help tour in the menu.

To adapt measuring to the way you work:

- Centimetres and millimetres
- Fractional inches (1/16) and decimal inches
- A start screen for choosing the measuring mode, which you can turn off
- Grid lines
- An edge margin for display cutouts and rounded corners
- Keep the screen on
- Light and dark theme, four background tones
- Seven measurement colours
- App language independent of the phone's system language

📱 WHERE CAN YOU USE IT?

Ruler is a handy helper at home, in the workshop, at the office and in everyday life.

Find out how long a screw is before you go to the shop, measure on fabric and paper, follow how tall a seedling has grown, or check whether a spare part will fit.

📊 HOW ACCURATE IS IT?

Accuracy depends first of all on your calibration and on your phone screen.

For the best result, calibrate Ruler before you measure. The app also marks readings that were taken without calibration.

Ruler promises no precision beyond the physical limits of your screen. The aim is to make the everyday measurements you can do with your phone as practical and as clear as possible.

No account. No ads while you measure. No unnecessary permissions.

Open your phone and start measuring.