How to measure a PDF plan to scale

You can measure a PDF drawing accurately without CAD or paid software. Here's how, in five steps, in your browser.

1. Open ScaleDraw

   Go to the board. There's nothing to install and no sign-up.

2. Import the PDF

   Open the menu (☰) and choose Import PDF…. The page lands on the board in a frame at its paper size.

3. Calibrate

   Press Calibrate (or C), then draw a line over a dimension you know: a dimensioned wall, a door, or the drawing's scale bar. Type the real length, such as 3.2 m or 900 mm.

4. Measure

   Choose Measure (or M) and drag between two points. The length shows on the line in real units. Lines and arrows you draw show their lengths too.

5. Check and export

   Measure a second known dimension to confirm the scale. Then export the page as an image from the menu.

Tips for accurate results

• Calibrate on the longest dimension you can find: small errors in where you click matter less.
• Zoom in when placing the ends of the calibration line.
• Don't trust drawings marked “not to scale”, or screenshots that have been stretched.
• Each picture keeps its own scale, so a site plan and a floor plan can sit on the same board.