Bubble level online — a free spirit level that runs in your browser
Updated July 3, 2026
This online bubble level turns your phone into an accurate spirit level, inclinometer, and angle finder using the gyroscope and accelerometer already built into your device. No app to download, no account, no cost — open the page, tap Start, and you're leveling.
Lay the phone flat to level a surface (table, shelf, washer, camper floor) or hold it on its edge like a torpedo level to level anything on a wall (picture frame, TV bracket, curtain rod). The tool switches between the two modes automatically, shows the exact tilt in degrees, and turns green with a small vibration the moment you hit level. Prefer it playful? Switch the skin and level with a sailboat on the high seas, a rolling marble, or a neon starship — same readings, more fun.
How to use your phone as a level
- Tap Start Level and allow motion & orientation access (iPhone shows a one-time permission prompt).
- Surface mode: lay the phone flat on the thing you're checking. The bubble drifts toward the high side; the surface is level when the bubble is centered and the ring turns green.
- Edge mode: hold the phone upright with its long edge against the frame, shelf, or rail. The readout shows how many degrees it's off horizontal — rotate until it reads 0.0°.
- Calibrate for best accuracy: phone cases and sensor drift can add a small constant error. Set the phone on a surface you trust, tap Calibrate, and the tool zeroes itself. One tap on Reset removes the offset.
- Hold freezes the reading so you can lift the phone and read the angle — handy when the phone is somewhere hard to see, like on top of a fridge.
What people level with this tool
Pictures, frames & gallery walls
Hold the phone's edge on top of the frame in edge mode and nudge until it reads 0.0°. Faster than fetching the toolbox level, and the degree readout beats eyeballing a bubble.
TV mounts & shelves
Level the bracket before you drill. A 1° error on a 65-inch TV is over an inch of visible droop at the far corner — this tool reads to 0.1°.
Washing machines & appliances
A washer that isn't level walks and bangs on spin. Put the phone flat on top in surface mode and adjust the feet until the bubble centers.
Campers, RVs & vans
Fridges need to run level and you'll sleep better too. Set the phone on the floor or counter, read the x/y split, and place your leveling blocks accordingly.
Pool tables, turntables & 3D printers
Precision toys reward patience: calibrate first on a known-flat reference, then chase the last half degree with shims.
Decks, fences & DIY builds
Use edge mode along a joist or rail as a quick site check when the real level is in the truck. For structural work, confirm with a proper tool before fastening.
How accurate is a phone level?
Modern phone accelerometers resolve tilt to roughly 0.1°, and after calibration real-world accuracy of 0.1–0.5° is typical — comparable to a decent hardware bubble level, and more readable because you get numbers instead of guessing at a bubble's position. Two habits improve it further: calibrate on a trusted surface, and take readings with the phone still rather than in motion.
For fine woodworking, machine setup, or anything structural, treat this as a fast field check and verify with a calibrated machinist level.
Bubble level, spirit level, inclinometer — what's the difference?
They're overlapping names for the same idea: an instrument that shows deviation from horizontal. Bubble level and spirit level both refer to the classic liquid-filled vial where an air bubble floats to the high side. An inclinometer (or clinometer, tilt meter, angle finder) reports the tilt as a number in degrees. This web app is all three at once: a visual bubble you can read at a glance, plus a digital degree readout when you need the exact angle.
Leveling guides
Step-by-step guides for the jobs people actually open this tool for:
- How to level a washing machine — stop the shaking and walking in about 10 minutes.
- How to hang a picture perfectly straight — the 57-inch rule, the two-hook trick, and a zero-guesswork tape template.
- How to level a camper or RV — side-to-side first, then front-to-back, and why your fridge cares.
Frequently asked questions
Can I really use my phone as a spirit level?
Yes. Every modern smartphone has an accelerometer that senses gravity, which is exactly what a bubble in a vial does. This page reads that sensor in your browser and displays it as a level — no app store, no install.
How accurate is it?
Typically within 0.1–0.5° after calibration — plenty for hanging pictures, mounting TVs, and leveling appliances or furniture. For fine woodworking or machine setup, use a calibrated machinist level.
Why does it ask for motion sensor permission?
Browsers require your consent before a page can read the gyroscope and accelerometer. All readings are processed on your device — nothing is uploaded, stored, or shared.
Does it work on iPhone and Android?
Yes. On iPhone, Safari shows a one-time permission prompt after you tap Start. Android Chrome usually starts immediately. Desktops and laptops don't have tilt sensors, so you'll see a demo — open the page on your phone for the real thing.
Which way should the bubble go?
Like a real vial, the bubble floats toward the high side. In the Marble and High Seas skins it's the opposite — marbles roll and boats drift downhill — which some people find more intuitive.
Does it work offline or in landscape?
Once the page is loaded it keeps working without a connection, and both portrait and landscape orientations read correctly. Your calibration and skin choice are remembered on your device.
Is it free?
Completely — no app install, no sign-up, no watermarks.