Ruler, Level & Protractor
Use your phone or monitor as a ruler (calibrated with a bank card), check level with the tilt sensor, and measure angles with an on-screen protractor. Measurements never go to a server.
The zoom level changed since calibration. Please calibrate again.
Hold a bank card (85.6 mm wide) against the dashed box and move the slider until the box is exactly as wide as the card. It only fits this screen.
Tap or drag on the ruler to see the length from the left end. Without calibration the browser's assumed size is used and may differ from reality.
Check level with your phone's tilt sensor. Lay it flat, or stand it up and rest the bottom edge on the object.
Sensors vary between devices. Use a real spirit level for precise work. Sensor values never go to a server.
Drag the red dot (or use arrow keys) to match the angle of an object on the screen. The center dot is the vertex.
How to use this tool
Use your phone when you have no ruler or spirit level. Use the screen as a ruler (calibrated with a credit card), check level with the tilt sensor, and measure angles with the on-screen protractor. Measurements are not sent to a server.
Frequently asked questions
Is the screen ruler accurate?
It reduces error by calibrating the screen against a credit card. Use a real ruler when you need precision.
How does the level work?
It uses the device's tilt sensor, so it is unavailable on devices without one or where permission is blocked.
Are measurements stored?
No. Measurements are not sent to a server.
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