How to measure a floor plan online

You don't need CAD software to measure a floor plan. If the plan shows one dimension you trust, ScaleDraw can turn every other line on it into real lengths and areas, in a browser tab.

1. Add the plan

   Open the board and drag the plan onto it: a PDF, a JPEG or PNG, or a screenshot. Each one lands in its own frame, locked so you can draw over it without moving it.

2. Calibrate on a dimension you know

   Press Calibrate, then drag from one end of a known dimension to the other: an overall width, a marked room size, or a door (usually about 0.8 to 0.9 m wide in the UK). Type its real length and press Enter.

3. Measure

   Press Measure (or M) and drag between any two points. The length appears on the line as you draw, in metres, millimetres, feet and inches or whatever unit you calibrated in.

4. Get areas

   Draw a rectangle over a room (R) and select it to see its size, area and perimeter. For an L-shaped or irregular room, use Lasso fill (G) to draw round it, then select the fill to see its area.

5. Save or share

   Use Menu → Save to keep the board as a file, or export it as a JPEG to send to someone.

Tips for accurate measurements

• Calibrate on the longest dimension you can find. A small slip in where you click matters much less over 8 m than over 80 cm.
• Zoom in when you place the ends of the calibration line.
• Check your scale against a second known dimension before relying on it.
• If a plan says “not to scale”, treat the result as a guide and confirm critical sizes on site.