Free Tool · Architects and Engineers
Scale Converter for Architects and Designers
Convert between architectural drawing scales instantly. Free tool for architects, designers, engineers, and students. In metric units: millimeters (mm), centimeters (cm), and meters (m).
Enter a measurement above to see the result.
Enter a measurement above to see the result.
Click a scale to set it as From Scale (Mode 1) or Target Scale (Mode 2):
Common Architectural Scales
Architectural drawings rely on scale to accurately represent real-world dimensions on paper or screen. Using an incorrect scale leads to sizing errors, miscommunication, and rework. This converter focuses on ratios architects use most (1:50, 1:100, and 1:200), helping you translate real-world dimensions into drawing measurements and back again.
Frequently Asked Questions
Know more about architectural scales and how to use this converter.
- Multiply the drawing measurement by the scale factor to get the real-world dimension. For example, 10mm at 1:100 = 10 × 100 = 1000mm (1 meter) in reality. To convert between two scales, multiply by the first scale factor and divide by the second. This converter does all of that automatically.
- 1:100 is the most common scale for standard floor plans. Use 1:50 for detailed plans showing room layouts and furniture. Use 1:200 for overview plans or when drawing larger buildings. Use 1:20 or 1:25 for detailed sections and wall details.
- At 1:50, every 1mm on paper represents 50mm (5cm) in reality. At 1:100, every 1mm represents 100mm (10cm). A 1:50 drawing is twice the size of a 1:100 drawing of the same building — it shows more detail but requires a larger sheet.
- Multiply your drawing measurement by 2. A wall shown as 50mm at 1:100 will be 100mm at 1:50. This converter does this automatically — enter your measurement, select 1:100 as the From Scale, and 1:50 as the To Scale.
- Yes. Next to each measurement field there is a unit switch with mm, cm, and m; the active unit is underlined and defaults to cm. Click m to type real-world dimensions directly, such as 3.5m, or mm for small drawing measurements. The result is always shown in the most readable unit: for example, 3.5m in real life is 7cm (70mm) on a 1:50 drawing.
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