Level, ruler, protractor, compass and sound meter.
SurfaceYour zeroLocked
0.0°
Lay it flat or stand it on an edgeFlat on a shelf or table, you get the bubble with two axes. Stand the phone on its edge against a frame or shelf for the tube level.
0.0 cm
Not calibrated
Bank card
Match a bank card
Hold any bank, ID or library card flat on the screen in the top corner, and resize the drawn card until it matches exactly.
Put one end of the thing you're measuring on the zero line, then drag the other handle to its far end. Drag the zero line too, to measure between two marks. Calibration is saved on this device.
60.0°Reflex 300.0°
Drag the two round handles to the arms of your angle, and the centre dot to its corner. Lay a small object on the screen, or line the arms up with a photo. Arrow keys nudge the selected arm.
0°NorthMagnetic north
Hold it flat, away from metalMagnets, cases with clasps, laptops and steel tables pull the needle. If it looks wrong, wave the phone in a figure of 8 a few times.
–dB
Estimate: phone mics aren't calibrated
Tap Start to measure
20406080100120
Min–
Avg–
Max–
0:00
Last minuteOffset +100 dB
How loud is that?
Nothing is recorded: the page reads the microphone's level and keeps only the numbers. For a closer reading, set the offset against a real sound level meter in Settings.
Bubble Level
Level, ruler, compass and sound meter · Free utilities app for your browser
A spirit level for your phone: lay it flat for a bubble level with degrees on two axes, or stand it on an edge for a tube level. It turns green with a tick at level, and you can set your own zero, lock a reading or calibrate the sensor by turning the phone around. There's also an on-screen ruler in centimetres and inches that you calibrate with a bank card, a protractor with two arms, a compass where your phone gives a heading, and a sound meter that estimates decibels with min, average and max. Nothing is recorded or uploaded.
Surface and edge level with degrees, green at 0°
Set your own zero, lock a reading, calibrate the sensor
On-screen ruler in cm and inches, calibrated with a bank card
Protractor with two draggable arms
Compass with degrees and true north
Sound meter: dB estimate, min, average, max and a live graph
Works offline
Private: stays on your device
No account or sign-up
Free to use. Optional one-time upgrade: Bubble Level Pro, $1.99 (no subscription), or every upgrade in every Yuzool app with Yuzool Plus, $19.99 once. Works on iPhone, Android, Mac and PC; add it to your Home Screen to open it like an app.