Enable the level sensor
Open this page on a compatible phone or tablet, press Enable Level Sensor and allow motion access if your browser requests it.
Use a compatible phone or tablet on HTTPS. Place the device on a clean, stable surface and press Enable Level Sensor. iPhone and iPad may show a motion-permission prompt. A thick case, camera bump, magnetic accessory or uneven phone back can affect the physical result.
Secure pageChecking
Motion sensorChecking
Orientation sensorChecking
Screen wake lockChecking
Two-axis surface levelSensor not started
—Left / right
—Front / back
—Total tilt
Level controls
Waiting for sensorSet Zero calibrates the current resting position. Use it on a known reference surface when a case or camera bump prevents the phone from sitting perfectly flat.
Precision settings
Saved on this device65%
Live diagnostics
No readings0 HzEvent rate
—Stability
0Samples
0°Screen rotation
Factory zeroCalibration
—Recent max
Current level report
Surface—X axis
—Y axis
—Total tilt
—Level state
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How to Use Your Phone as a Bubble Level
Measure a surface, edge, vertical object or slope in three quick steps.
Place and calibrate
Set the device on the object or hold an edge against it. Press Set Zero if you need to compensate for a case, camera bump or reference angle.
Center the bubble
Adjust the object until the bubble enters the target and the status reads Level. Freeze, copy or share the final digital level reading.
Phone Bubble Level, Spirit Level and Inclinometer Modes
One mobile level tool for flat surfaces, horizontal edges, vertical plumb checks and angle measurements.
Surface bubble level
Lay the phone flat to measure front-to-back and side-to-side tilt together. This is useful for tables, appliances, washing machines, camera platforms and floor checks.
Horizontal spirit level
Use the long edge of the phone to check shelves, frames, rails, worktops and furniture. The horizontal mode emphasizes one axis for easier reading.
Vertical plumb level
Hold the phone against a post, wall edge, cabinet side or picture frame to check whether it is upright and plumb.
Digital inclinometer
Measure tilt angle, percent grade or millimetres per metre for ramps, roofs, drainage slopes, tripods and general angle-finder tasks.
Caravan and RV leveling
Place the device on a stable interior reference surface to compare side-to-side and front-to-back tilt while adjusting supports or parking position.
Camera and tripod level
Check a tripod plate, phone mount or camera support before recording horizons, panoramas, product photos or architectural scenes.
Professional Bubble Level Features
A responsive mobile leveling engine designed around browser motion sensors and real-world usability.
Two-axis live bubble
See horizontal and vertical tilt together with a large circular bubble, crosshair target and color-coded level state.
Surface and edge modes
Switch between surface level, horizontal level, vertical plumb and angle-finder layouts without reloading the page.
Adjustable tolerance
Choose precision from ±0.1° to ±2.0° according to the task, sensor stability and physical phone shape.
Degrees, grade and mm/m
Display angle in degrees, percent slope or millimetres per metre for construction, drainage and ramp measurements.
Mobile full-screen mode
Use a large distraction-free bubble with notch-safe spacing in portrait or landscape orientation.
Custom zero calibration
Compensate for a protective case, raised camera module or intentionally sloped reference surface and optionally remember the offset locally.
Stability and event diagnostics
Monitor recent variation, maximum deviation, sample count and browser sensor-event rate to judge reading quality.
Level feedback
Optional vibration and a short audio cue notify you when the selected axis or surface enters the chosen tolerance.
What Is an Online Bubble Level?
An online bubble level uses motion and orientation information exposed by a compatible phone or tablet browser to estimate tilt. It can behave like a digital spirit level, pocket inclinometer, angle finder, slope meter or plumb checker. Instead of watching a liquid vial, you center a virtual bubble and read the measured angle on screen.
This phone level is useful when a physical carpenter’s level is not nearby, when you need a quick second opinion, or when a large mobile display is easier to read in a tight space. It can help level shelves, pictures, tables, washing machines, refrigerators, worktops, camera mounts, tripods, caravans and many other objects.
How the Phone Level Sensor Works
The tool prefers acceleration data that includes gravity because the direction of gravity provides a practical reference for surface tilt. It converts gravity on the device’s X, Y and Z axes into two tilt angles, adjusts those axes for portrait or landscape screen rotation, applies optional smoothing and subtracts your zero calibration. When motion data is unavailable, the page can use device-orientation angles as a fallback.
Browser readings are high-level sensor estimates rather than laboratory calibration data. Sensor quality, operating-system filtering, browser timing and the device’s physical construction influence the result. The live event rate shown by the page is a browser delivery estimate, not the raw hardware sampling frequency.
Bubble Level Accuracy and Calibration
A modern phone can be useful for ordinary household leveling, but accuracy varies. For the best result, remove a thick or uneven case, avoid resting on a camera bump, use a clean rigid surface and calibrate against a trusted reference. Repeat the reading after rotating the phone 180 degrees. If the two results disagree significantly, average them or use a certified physical level for critical work.
The tolerance setting controls when the page says Level. A narrow ±0.1° threshold is demanding and may flicker on noisy sensors. The default ±0.5° setting is more practical for everyday mobile use. Calibration changes the zero reference; it does not repair a faulty sensor or guarantee construction-grade accuracy.
Using the Inclinometer and Slope Meter
Angle Finder mode shows total tilt from the calibrated reference. Degrees are easiest for general angle measurement. Percent grade is common for ramps and drainage: the tool converts angle to rise divided by run multiplied by 100. Millimetres per metre expresses the same slope as vertical millimetres of rise over one horizontal metre.
- 0° means no measured tilt from the calibrated reference.
- 1° is approximately 1.75% grade or 17.5 mm per metre.
- 5° is approximately 8.75% grade or 87.5 mm per metre.
- 45° equals 100% grade.
Best Uses for a Mobile Spirit Level
Use the surface bubble for tables, appliances and platforms. Use horizontal mode for shelves, frames and rails. Use vertical mode for posts, cabinet sides and plumb checks. Use Angle Finder mode for ramps, roof pitch approximations, tripod heads, vehicle leveling and general slope comparisons.
For safety-critical building, structural, electrical, gas, machine alignment or accessibility work, verify the result with an appropriate calibrated tool and applicable standards. This browser utility is a convenient general-purpose aid, not a certified surveying or construction instrument.
Privacy and Browser Requirements
Live orientation and motion readings stay in the page and are not uploaded to CorrectionCopy. Settings and an optional calibration offset may be stored locally on your device. The page sends only an anonymous aggregate completion count and aggregate star rating to Firebase.
Sensor APIs normally require HTTPS. Some iPhone and iPad browsers require a permission request initiated by tapping a button. Desktop computers often have no suitable orientation sensor, so the best experience is on a compatible mobile phone or tablet.
Practical limitation: phone sensors can help with everyday leveling, but a raised camera module, bent case, soft surface or imperfectly flat phone body can create a physical offset even when the electronic sensor is accurate.
Bubble Level Reading Guide
Interpret the live angle, slope and stability values before trusting a final position.
| Reading | Meaning | Useful response |
|---|---|---|
| Level | The selected axis or surface is within your chosen tolerance. | Freeze or copy the result, then recheck after moving the phone or rotating it 180°. |
| Near level | The reading is close but outside the selected tolerance. | Make a small adjustment and wait for the stability value to settle. |
| Tilted | The object is clearly outside the chosen level threshold. | Follow the bubble direction or use the signed X/Y values to adjust the high side. |
| Low stability | The phone is moving, vibrating or receiving noisy sensor updates. | Stop touching the device, use a rigid surface and increase smoothing if needed. |
| Different result after rotation | The phone body, case, camera bump or sensor zero may be offset. | Calibrate on a trusted reference or average readings from opposite orientations. |
| No sensor data | The browser, permission, HTTPS status or hardware does not provide usable events. | Use a current mobile browser, open the HTTPS page and press Enable Level Sensor again. |
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Bubble Level Frequently Asked Questions
Answers about phone level accuracy, calibration, browser permission, slope measurement and mobile compatibility.
It is a browser tool that uses a compatible phone or tablet motion sensor to estimate tilt and display a virtual spirit-level bubble, angle and slope reading.
Press Enable Level Sensor, allow permission if requested, place a flat phone edge or back against the object and adjust until the bubble enters the center target.
It can be useful for ordinary household work, but accuracy varies by sensor, case, camera bump and phone body. Verify critical work with a calibrated physical level.
Calibration defines the current position as zero and can compensate for an uneven case, camera module or intentionally sloped reference surface.
Measure a stable surface, rotate the phone 180 degrees and measure again. Large disagreement suggests a physical offset, sensor bias or unstable reference.
Compatible iPhone and iPad browsers can provide motion data, but Safari may require a permission prompt triggered by the Enable Level Sensor button.
Many current Android browsers expose motion or orientation readings on HTTPS pages. Availability still depends on the device, browser and permission settings.
Some browsers allow sensor access only after a direct user action. The button provides that user interaction and requests permission where required.
Modern browsers restrict motion and orientation APIs to secure contexts to protect access to device sensor information.
Yes. Choose Percent grade in Display units. The tool converts the measured angle using the tangent of the angle multiplied by 100.
It expresses slope as vertical millimetres of rise or fall over one horizontal metre. It is another way to describe a small inclination.
Yes. Angle Finder mode shows the total tilt from the calibrated reference and can display degrees, percent grade or millimetres per metre.
Use Vertical / Plumb mode and hold a straight phone edge against the object. Keep the device stable and calibrate if the case is uneven.
You can use it for a convenient comparison on a stable interior surface, but verify critical support and safety decisions with appropriate leveling equipment.
A thick case, raised lip or camera bump can stop the device body from lying parallel to the measured surface. Remove it or set a custom zero on a trusted reference.
Higher smoothing produces a steadier bubble but responds more slowly. The default is a practical balance; reduce it for fast movement or increase it for noisy sensors.
Small sensor noise, vibration, a flexible surface or ongoing device processing can move the reading. Wait for stability, increase smoothing and avoid touching the phone.
Most desktops and many laptops do not expose a suitable motion sensor, so this tool is primarily intended for phones and tablets.
No. Live sensor readings stay in the page. Only an anonymous completion count and aggregate star rating are sent to Firebase.
No. It is a convenient browser-based mobile level for general use. Use calibrated professional equipment for regulated, structural or safety-critical work.