Bubble Level

Horizontal level · side-to-side tilt

0.0

Waiting for sensor

Tap Start to read the sensor

Place the phone flat on the surface with the screen facing up.

How do you check if a surface is level?

Place your phone flat on the surface with the screen facing up. Make sure the phone is not hanging over an edge. Tap Check Level, then wait a second for the reading to settle.

The bubble moves toward the higher side. For example, if it moves to the left, the left side is higher. Lower the left side or raise the right side.

The number above the bubble shows the angle of the surface. A reading between -0.2° and 0.2° is considered level. The display will turn green and your phone will vibrate briefly.

For comparison, an angle of 1° means a height difference of about 17 mm over one metre.

What if the reading looks wrong?

First, remove your phone case. A thick case or raised camera bump can lift one corner of the phone and affect the result.

Next, place the phone on a surface you know is level and tap Calibrate. This saves that position as zero for all level tools on the website. Tap Reset to remove the calibration.

You can also check the result by turning your phone 180 degrees in the same spot. You should get almost the same number in the opposite direction. A small difference may come from the phone’s sensor.

Need to measure another direction? Try the Vertical Level or use the 2-Axis Level to check both directions at once.

Frequently asked questions

How accurate is a phone bubble level?

After calibration, most phones can measure within about 0.1° to 0.3°. That is usually accurate enough for shelves, furniture, appliances, and picture frames.

The result also depends on how flat the phone sits. For construction or safety-related work, use a proper spirit level and straightedge.

Which side should I raise?

The bubble moves toward the higher side. Lower that side or raise the opposite side. The message below the number also tells you which side needs adjusting.

Why does the bubble move on a table that looks flat?

A surface can look flat without being perfectly level. Wooden tables can bend, worktops may sag, and some floors are built with a slight slope. Your phone’s sensor may also have a small offset, which calibration can correct.

Does it work without an internet connection?

Yes. Once the page has loaded, the level works directly in your browser. Your measurements are not sent or saved.

Why do I need to tap Check Level?

On iPhones and iPads, Safari requires you to tap a button before a website can use motion sensors. This privacy feature stops websites from reading sensor data without your permission.

Most Android browsers allow access automatically, but you can still use the same Check Level button.

Can I use it to level a picture frame?

Yes. Hold the phone against the top edge of the frame so you measure the frame itself, not the glass.

If the picture hangs from a wire, it may move slightly after you let go. Check it again after a minute.

Why is the bubble not moving?

Motion access may have been blocked, or your device may not have the required sensor. This tool usually will not work on desktop computers or laptops, so open the page on a phone or tablet.

On Android, check your browser’s Site settings and make sure Motion sensors are allowed.

What can a phone level be used for?

A calibrated phone level is useful for everyday jobs such as hanging shelves, adjusting furniture, levelling appliances, and straightening picture frames.

However, a phone is not a certified measuring tool. Use a professional level for structural, construction, or safety-critical work.