Calibrate your photo
Take a straight-on photo with a tape measure or another known length in the same flat plane as the distance you want to measure. Keep the camera as square to the surface as possible. Perspective and lens distortion can change the estimate.
Tap the two ends of the reference, then tap the two ends of the distance to measure.
Choose a photo to begin.
Use this length in Square Footage CalculatorThe image stays in this browser. Check measurements with a tape before ordering materials.
How to estimate a distance from a photo
Place a tape measure or another known-length reference beside the target on the same flat surface. Capture both in one image. Select the reference endpoints first and enter their real-world distance, then select the two target endpoints. If a 2 ft reference spans 100 pixels and the target spans 250 pixels at the same scale, the estimated length is 5 ft.
When a photo measurement can be misleading
Objects farther from the camera can look smaller even when they are the same length. A tilted camera and a wide-angle lens can also distort the estimate. Use the photo tool for planning and check the result with a physical measurement before buying or cutting material. For square footage, measure the second dimension separately and enter it after transferring the first length.