SYNTHLUCIDA · LEVEL
Always level
Free digital bubble level, angle meter, ruler, flashlight, unit converter and calculator – right in your browser, no install needed

SYNTHLUCIDA LEVEL – free digital bubble level and angle meter

Apps
Features
Waiting for sensors…
0.0°
Tilt X
0.0°
Tilt Y
Demo mode (no sensors)
Sound when level
Vibration when level
About the app

SYNTHLUCIDA LEVEL is a free web-based bubble level and angle meter that uses your phone's gyroscope and accelerometer. Switch between Surface mode for two-axis leveling (e.g. shelves, appliances) and Angle / slope mode for precisely measuring the slope of a single edge (e.g. ramps, stairs, vertical walls).

Calibration: if your phone or case slightly skews the reading, place the device on a known flat surface and tap Calibrate zero – the current tilt is saved as the reference zero.

The bubble and the digital angle readout turn green once the tilt is close enough to zero (or to the selected target of 0° / 45° / 90°). You can optionally enable a sound and vibration confirmation. Everything is calculated right on your device, nothing is sent to a server – saved readings stay only in your browser.

Ruler: switch to the Ruler tab to measure small objects right on your phone's screen. You can toggle an inch scale alongside the centimeter one at the top. Since the browser doesn't know your screen's real physical size, the default scale is only approximate – tap Calibrate, hold a bank or ID card against the screen (85.6 mm wide) and drag the slider until the frame matches its edges exactly. The calibration is saved in your browser for next time.

Flashlight: the Flashlight tab tries to turn on your phone's real camera flash – this mainly works on Android with Chrome. If your device can't control the flash from a website (typically iPhone/Safari), the app lights up the screen at full brightness instead, with a choice of color (white, warm white, red, blue). Turn it off with the button, by tapping anywhere on the lit screen, or by switching to another mode. The Start SOS blink button flashes the light in the international Morse SOS pattern (· · · — — — · · ·) on a continuous loop until you turn it off again.

Unit converter: the Convert tab offers two conversions – length (mm, cm, m, km, inches, feet, yards) and angle (degrees, radians, gradians, slope in %, ratio 1:n). Type a value into any field and the rest update automatically. In the angle section, a "Use live angle" button inserts the live reading from the Angle tab.

Calculator: the Calculator tab is a classic calculator for quick calculations right while you measure (addition, subtraction, multiplication, division, percentages) – it works with touch or your keyboard.

Accuracy depends on the quality of the specific phone's sensors. For professional or construction use, we recommend verifying the result with a traditional spirit level.
Frequently asked questions
How does a digital bubble level in the browser work?
It reads data from the gyroscope and accelerometer via the DeviceOrientation API and converts it into degrees of tilt in real time. It works directly in the browser, with no app install required.
Why do I need to allow sensor access?
On iPhone and iPad, the browser's security policy requires it – just tap "Enable sensors" and confirm the system prompt.
Does the level work on a computer too?
Most computers don't have motion sensors. Turn on demo mode with the slider to try the interface even without real measurement, or open the app on a mobile phone.
How accurate is a web-based level?
Usually within a few tenths to one degree, depending on the quality of the phone's sensors. For the best result, calibrate on a known flat surface before measuring.
How accurate is the on-screen ruler?
By default it uses the browser's reference pixel size, which is only approximate. For accurate mm/inch marks, tap "Calibrate" in the Ruler tab and match the frame to a bank or ID card (85.6 mm wide) – the app remembers this for your device.
Why does the flashlight just light up the screen instead of the camera flash?
Turning on the real camera flash from a website only works on some Android/Chrome devices. When that's not available (e.g. on iPhone), the app lights up the screen at full brightness instead, which works everywhere.
Tap to turn off