Simple length/distance measurements in photo / image files, based on a known reference object size (online in your browser and no data is transferred to the server).
Note that this method is only good for rough estimates, due to camera perspective (and lens imperfections).
It's best if the reference object and whatever you want to measure are near each other and at the same distance from the camera.
- , drop, paste an image file or URL anywhere onto this page (there's one exception: you can't drop a local image from another browser tab). Large images will be scaled down to the page width.
- Create the reference dimension (red) by click-and-dragging the first measurement line onto an object with known size.
- Create measurement lines (green) by click-and-dragging (remove them by clicking on the 'remove' link in the measurement table below).
- Enter the real-world length of the first dimension as reference - the other measurements will be scaled accordingly.
- You can enter a unit, it'll show up in the results (it does not affect the measurements).
- Leave empty if you want to measure pixels (pixel measurements will be off for downscaled images).
- Hold CTRL while dragging to create horizontal/vertical lines
- Hit ESC to clear