How to Check if a Surface is Level

Place your phone flat on whatever you're checking — a shelf, a table, a washing machine that's been making weird noises. Tap Check Level and watch the bubble. If it sits dead-center between the groove marks, you're level. If it drifts to one side, that side is lower.

The number shows exactly how many degrees off you are. Anything under 0.2° is close enough for most jobs — that's what the green tolerance zone marks. Your phone will give a short vibration when you hit that sweet spot.

Hit Calibrate if you want to set the current position as your new zero — handy if your phone case is slightly uneven. Reset brings it back to the factory baseline.

For front-to-back tilt, switch to the Vertical Level. Need both directions at once? The 2-Axis Level shows everything in one view.

Frequently Asked Questions

How accurate is a phone bubble level?

Modern phone accelerometers are accurate to roughly ±0.1°–0.3°, which is plenty for hanging pictures, levelling furniture, or checking if a floor slopes. For professional construction work you'd still want a proper spirit level, but for everyday tasks your phone does a surprisingly good job.

Why does the bubble move when my phone is on a flat table?

Most tables aren't actually flat — they have slight imperfections. Also, your phone's sensor has a tiny built-in offset from manufacturing. That's what the Calibrate button is for. Put the phone on your surface, tap Calibrate, and it'll treat that position as zero.

Does this work without internet?

Once the page has loaded, yes. All the sensor reading and bubble movement happens locally on your device. Nothing gets sent anywhere — your tilt data stays on your phone.

Why do I need to tap "Check Level" first?

Some phones (especially iPhones on iOS 13+) require you to explicitly grant permission before a website can access motion sensors. The button triggers that permission request. On Android it usually works right away, but the button keeps the experience consistent.

Can I use this to level a picture frame?

Absolutely — it's one of the most common uses. Hold your phone against the top edge of the frame and adjust until the bubble centers. For wall-mounted items, the Vertical Level might be more intuitive since it measures front-to-back tilt.

The bubble isn't moving at all

Make sure you tapped Check Level and granted sensor permission. If you're on a desktop or laptop, there's no motion sensor — scan the QR code to open it on your phone instead. On some Android browsers, you may need to enable "Motion sensors" in site settings.