Loading Calculator...
Please wait a moment
Please wait a moment
Convert between scale and actual sizes
Work with scale ratios for maps, models, and drawings. Convert between scaled and actual measurements.
Model : Actual
Model size
Enter values to calculate
Scale ratios show the relationship between measurements on a model, map, or drawing and the actual size. A scale of 1:100 means 1 unit on the model equals 100 units in reality.
1:50, 1:100, 1:200 scales for building plans and models
1:50,000 to 1:250,000 for topographic and road maps
1:12, 1:24, 1:48 for toy cars, trains, and figurines
A 1:100 scale means every 1 unit on your model/map represents 100 units in reality. For example, 1 cm on a drawing equals 100 cm (1 meter) in actual size.
Multiply the model measurement by the second number in the scale ratio. For a 1:100 scale, if something measures 5 cm on the model, it's 5 × 100 = 500 cm (5 meters) in reality.
Divide the actual measurement by the second number in the scale ratio. For a 1:100 scale, a 300 cm actual wall would be 300 ÷ 100 = 3 cm on the model.
1:50 is twice as large as 1:100. A model at 1:50 scale will be twice the size of the same object at 1:100 scale. Smaller second numbers mean larger models.
Yes! Scales can be written as ratios (1:100), fractions (1/100), or with units (1 cm = 1 m). They all represent the same relationship.
Common scales are 1:100 for floor plans, 1:50 for detailed plans, 1:20 for construction details, and 1:200 or 1:500 for site plans. The choice depends on the level of detail needed.
Use a scale ruler or regular ruler. Measure the distance on the drawing, then multiply by the scale factor. For 1:100, 2.5 cm on drawing = 2.5 × 100 = 250 cm actual.
Yes, but you must square the scale factor. For 1:100 scale, areas are multiplied by 100² = 10,000. A 1 cm² area on the model equals 10,000 cm² (1 m²) in reality.