Open this page on your phone, press Start, then lay the phone on a table or hold its edge against a shelf, frame or door jamb. The bubble moves to the higher side and turns green when it is perfectly level.
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0.0°
X 0.0°Y 0.0°
Slope 0.0%0 mm per metre
📱 Open on your phone
Computers usually have no tilt sensor. Scan this QR code with your phone camera to open the bubble level on your phone.
ℹ️ Phone sensors are accurate enough for everyday jobs around the house (about 0.1 to 0.5 degrees after calibration). For construction work that needs high precision, use a calibrated spirit level or laser level. Sensor data is not sent anywhere.
How to Use the Digital Bubble Level
Press Start and put the phone down. In Surface mode, the round bubble shows tilt in every direction, ideal for tables, floors and washing machines. In Edge mode the phone stands up and the tube bubble shows tilt in one direction, ideal for shelves, picture frames and door frames. The angle, percent slope and mm per metre appear under the bubble.
0.1°
Fine readout
Angles are shown to one decimal place.
2
Measuring modes
Flat surface and edge, chosen automatically.
%
Percent and mm/m
The units builders use for drains and floors.
2-step
Calibration
Removes the error caused by the camera bump.
Conversion Table: Degrees, Percent and mm per Metre
Slope can be written in several units. This table helps translate the figures in drawings or installation instructions:
Angle
Percent
mm per metre
0.25°
0.4%
4
0.50°
0.9%
9
0.57°
1.0%
10
1°
1.7%
17
1.15°
2.0%
20
2°
3.5%
35
3°
5.2%
52
5°
8.7%
87
10°
17.6%
176
15°
26.8%
268
30°
57.7%
577
45°
100.0%
1,000
When You Need a Level
Wall shelves and cabinets. A sloping shelf lets things slide and makes cabinet doors swing on their own.
Washing machines and fridges. A washing machine that is not level shakes hard on the spin cycle. Adjust its feet until the bubble is centred.
Picture frames and TVs. The eye is very sensitive to crooked lines on a wall. Hold the edge of the phone against the top of the frame.
Bathroom floors and drains. Bathroom floors and waste pipes should actually slope slightly towards the drain, usually around 1 to 2 percent.
Desks, cameras and projectors. Make sure a tripod, workbench or projector is level so the picture is not tilted.
Frequently Asked Questions
Press Start and allow motion sensor access if asked (iPhone always asks). For flat surfaces such as a table or floor, lay the phone on its back. For a shelf, picture frame or door frame, stand the phone on its long edge against the object. Auto mode picks the right view by itself.
The back of a phone is rarely perfectly flat because of the camera bump and the case. Do the 2-step calibration: place the phone on the surface, press Calibrate, turn the phone 180 degrees in the same spot and press again. This removes the error from the phone's shape and from the surface slope at the same time.
After calibration, phone accelerometers are typically accurate to about 0.1 to 0.5 degrees, which is plenty for hanging shelves, cabinets, washing machines or picture frames. Results are best when the phone is still and not held. For structural work or precision machinery, use a builder's level or a laser.
Percent slope is the rise divided by the horizontal run, times 100. A 1% slope drops 1 cm over every metre, or 10 mm per metre. These units are common for drains, bathrooms and roofs, while degrees are more common for the angle of objects.
Most laptops and desktop computers have no tilt sensor. Open this page on a phone or tablet; you can scan the QR code shown on your computer screen to open it straight away on your phone.
Since iOS 13, Safari asks before a website can read the motion and orientation sensors. Choose Allow. If you denied it, close the tab and open this page again to be asked again.
Hold freezes the numbers on screen. It is useful when the screen is hard to see while measuring, for example on top of a tall wardrobe or behind a washing machine. Take the phone back and read the held value.
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