Uwarp

Upload a photo to measure a distance.

Or try an example

Image size appears after the photo loads.

Click two points on the photo.

The first line you scale from sets the unit. Later lines use that same scale.

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Measure on an image

Click two points on a photo and read the pixel distance. Set a known length to scale later lines. Free, no sign-in.

What this photo measure does

Click two points on a photo and read the straight-line distance in pixels. If you know the real length of that line, set it as the scale and later lines show the same unit. File size and the stored width and height are on Image Size Finder. Measuring a box on the screen, in CSS pixels, is on Pixel Ruler.

What you can read

The photo stays in the page. The numbers update from the two points you click.

  1. Pixel distance: The length is the straight line between the two clicks, in pixels of the loaded photo.

  2. A scale you set: Enter a known length and a unit, then use the current line as the scale for the next lines.

  3. Image size: The loaded width and height stay on screen next to the distance.

How to measure on a photo

Load a photo, click twice, and read the line.

  1. Load a photo

    Use an example or upload a PNG, JPEG, or WebP.

  2. Click two points

    The first click starts the line. The second click ends it. A third click starts a new line.

  3. Set a scale when you need units

    Type the real length of the current line and choose Use this line as the scale.

Tips

How to get a length you can trust.
  • 01

    Scale from a known edge

    A door, a ruler in the frame, or a printed mark gives the later lines a real unit.

  • 02

    Click the same photo

    A new upload clears the line and the scale.

  • 03

    Keep the file size check separate

    Byte size and the original file dimensions are on Image Size Finder.

When to use this page

Jobs this measure tool is built for.

  • A distance in a photo

    Read how many pixels separate two points.

  • A scaled length

    Turn that pixel line into centimeters, inches, or any unit you type.

  • A quick size check

    See the loaded width and height before you crop or resize.

What you get

A line and a number, in the browser.

  1. No account: The photo stays in the page. There is no sign-in step.

  2. One scale for the session: After you set the scale, each new line uses it.

  3. A fresh line: Clear drops the points and the scale.

Technical details

How the distance is calculated.
Input
PNG, JPEG, or WebP. Very large photos are limited to 8192 pixels on the long edge.
Distance
The length is the hypotenuse of the horizontal and vertical pixel gaps.
Scale
Unit length equals pixels times the known length, divided by the pixel length of the scale line.
Where it runs
In your browser.

Sources & References

Where the distance math and the canvas drawing come from.

Frequently Asked Questions

Quick answers about this tool—open a question to read more.