Free tools / Drawing
Reverse Scale Finder
Work out the scale of an unlabelled drawing from one known dimension.
Why this exists. Almost every architect has been handed a drawing with no reliable scale. Only one site in the world does this properly.
Everything here is calculated in your browser. Your numbers are never sent anywhere, stored or seen by us.
Drawing scale1:50Effectively 1:50 (standard working scale).
- Measured on drawing
- 24.00 mm
- Real length
- 1,200.0 mm (1.200 m)
- Scale ratio
- 1:50.00
- Nearest standard scale
- 1:50 (standard working scale)
| On the drawing | Real, metric | Real, imperial |
|---|---|---|
| 1 mm on the drawing | 0.050 m | 0.16 ft |
| 2 mm on the drawing | 0.100 m | 0.33 ft |
| 5 mm on the drawing | 0.250 m | 0.82 ft |
| 10 mm on the drawing | 0.500 m | 1.64 ft |
| 20 mm on the drawing | 1.000 m | 3.28 ft |
This matches 1:50 (standard working scale) closely enough to rely on.
How this is calculated
- Accuracy depends entirely on the measurement. Measure the longest known dimension you can find, because a one millimetre error on a short element becomes a large error on the derived scale.
- If the drawing has been photocopied or exported at an odd percentage, it may not sit on any standard scale at all. That is a real answer, not a failure.
This is a planning estimate, not professional advice. Read the full disclaimer.
Built because architects need it and nobody made it.
Finding the gap and filling it is the same method ScaleArc uses to get practices found online.
Talk to the founder