Gyroscope100% client-side. No sensor or calibration data leaves your device.

Online Inclinometer

Measure the slope of any surface in degrees, grade percentage, rise/run ratio, and roof pitch — directly in your browser.

Enable Tilt Sensors

Authorize browser tilt sensors to measure precise surface slope angle.

Not level

Angle

0.0°

Grade (%)

0.0%

Rise / Run

1 : ∞

Roof Pitch (in 12)

0 / 12

-90°

+90°

0°

How to Use the Inclinometer

The online inclinometer measures the angle of a surface relative to horizontal using your device's tilt sensors. Place your phone on the surface you want to measure and read the angle in real time.

The tool also displays grade percentage, rise/run ratio, and roof pitch — all calculated from the measured angle. Accuracy depends on your device's sensors; no additional processing is applied by this page.

What Is an Inclinometer Used For?

An inclinometer measures the exact tilt of a surface relative to horizontal. It is handy for checking roof slopes, ramp inclinations, shelf alignment, worktop angle, or any situation where you need a quick, precise slope reading without a physical instrument.

How to Read the Inclinometer

The main angle appears in degrees, along with a status label (Level, Nearly Level, Upward Slope, or Downward Slope). Below the angle, the grade percentage shows slope steepness, the rise/run ratio shows vertical proportion per unit of horizontal distance, and the roof pitch shows inches of rise per 12 inches of horizontal run — standard notation in North American construction.

For other measurement tools, also see: the online compass, the spirit level, the online ruler, or the sun compass.

Inclinometer FAQ

How do I use the online inclinometer?▼

Tap 'Enable Tilt Sensors' on your phone, then place it on the surface to measure. The angle and converted values update in real time. On desktop, move your cursor up and down to simulate tilt.

What does the inclinometer measure?▼

It measures the angle of a surface relative to horizontal, in degrees. It also calculates grade percentage, rise/run ratio, and roof pitch from that angle.

What is grade percentage?▼

Grade percentage equals the tangent of the angle multiplied by 100. A 45° slope is 100%. A 100% grade is steep but not vertical — a perfectly vertical surface would approach infinity.

Can I use the inclinometer on my phone and computer?▼

Yes. On a phone or tablet, the tool reads your device's tilt sensors for real measurements. On a desktop computer, a simulation mode lets you preview the tool with your mouse cursor. For actual readings, use a mobile device.

Does the inclinometer need calibration?▼

No calibration is required. The 'Zero Relative Angle' button simply sets the current tilt as a new reference point — useful for compensating for a phone case or comparing slopes, but not needed for normal use.

100% client-side. No sensor or calibration data leaves your device.

No tracking pixels. No analytics. No account. Sensor data and your calibration live only in this browser tab.