What is Level / Bubble Level?

A digital spirit level that uses your device's orientation sensors to measure tilt. Check whether surfaces are horizontal or vertical — handy for hanging pictures, leveling shelves, or aligning anything without a physical level.

The tool reads the gyroscope and accelerometer on your phone or laptop to show tilt in degrees along two axes. A green bubble means under 0.5 degrees off, which is close enough for hanging a picture frame. Calibration zeroes out factory sensor drift so a reading of 0.0 actually matches your reference surface.

How to use

1. Place your device flat on the surface you want to check — the bubble indicator shows real-time tilt angle in degrees.
2. Switch to Wall mode and hold the device flat against a vertical surface — the indicator becomes a single-axis plumb bar for checking door frames, posts, and wall edges.
3. Tap the calibrate button on a known-flat surface to zero out any sensor offset for more accurate readings.

When to use

• Hanging shelves, mirrors, and frames when you don't own a physical bubble level.
• Checking that a washing machine, fridge, or pool table sits level on the floor.
• Aligning camera tripods and recording surfaces before a video shoot.

Result

You're hanging a shelf and need to verify it's level. Place your phone on the shelf — the bubble reads 1.2 degrees off. Shim the left side until the display reads 0.0 degrees, then secure the brackets.

FAQ

How accurate is a phone-based level compared to a real spirit level?

After calibration, typical accuracy is around 0.3 to 0.5 degrees, which is good enough for hanging frames or aligning furniture. A machinist's level reaches 0.01 degrees, so for cabinet fitting or precision work, use a physical level.

Why does my reading show a tilt when the surface is clearly flat?

Phone cases, raised camera bumps, and curved laptop edges all lift one side. Place the device on the surface, hit calibrate, then move it without rotating. The tool will treat your starting position as the new zero. For a tighter zero, use two-point calibration: capture, flip the device 180°, and capture again so any built-in sensor bias cancels out.

It says my device has no orientation sensor. What's going on?

Most desktops and a few older tablets ship without a gyroscope or accelerometer. The DeviceOrientation API returns nothing on those machines. Try opening the page on a phone instead, which always has the right hardware.

On iPhone the level won't start. Why?

Since iOS 13 Safari requires you to tap a button before it grants motion access. Tap the start button once and pick allow on the permission prompt. If you blocked it earlier, reset the permission under Settings > Safari > Motion & Orientation Access.

Can I use this for vertical surfaces like door frames?

Yes. Switch on Wall mode at the top of the card — the round bullseye changes into a vertical bar that travels up and down with your left-right tilt, so you can press the long edge of the device against a post or door frame and read plumb directly. The 0.5 degree threshold still applies, and you can tap Hold once you have a steady reading to freeze the number while you pull the device away.

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