Scale Conversion Calculator – Convert Measurements to a Scaled Size

Scale a measurement to a larger or smaller measurement, which is useful for architecture, modeling, and other projects. You can also add the real size and scaled size to find the scale factor.

  • Find Scale Size
  • Find the Scale Factor

Find the Scaled Size

Find the Scale Factor

Scaled Results:

architect's scale measuring rule

How to Scale a Measurement Larger or Smaller

Making a measurement smaller or larger, known as scale conversion, requires a common scale factor, which you can use to multiply or divide all measurements by.

To scale a measurement to a smaller measurement, for instance, when making a blueprint, simply divide the real measurement by the scale factor. The scale factor is commonly expressed as 1:n or 1/n, where n is the factor.

For example, if the scale factor is 1:8 and the real measurement is 32, divide 32 ÷ 8 = 4 to convert.

To convert a measurement to a larger measurement, simply multiply the real measurement by the scale factor. For example, if the scale factor is 1:8 and the measured length is 4, multiply 4 × 8 = 32 to convert.

Reducing the Scale Factor

The methods above to convert a measurement assume the scale factor is in the form of 1:n or 1/n, which means some additional work is needed if the ratio is 2:3, for example. When the scale factor is not in an even 1:n ratio, you'll need to reduce it to 1:n.

Use our ratio calculator to reduce a ratio. You can also reduce a ratio by dividing both the numerator and the denominator by the numerator.

For example: reduce 2/3 by dividing both numbers by 2, which would be 1/1.5 or 1:1.5.

2 ÷ 2 = 1
3 ÷ 2 = 1.5
scale factor = 1:1.5

Commonly Used Architectural Scales

Scale factors for common architectural scales
Architectural Scale Scale Factor
1/16″ = 1′ 1:192
3/32″ = 1′ 1:128
1/8″ = 1′ 1:96
3/16″ = 1′ 1:64
1/4″ = 1′ 1:48
3/8″ = 1′ 1:32
1/2″ = 1′ 1:24
3/4″ = 1′ 1:16
1″ = 1′ 1:12
1 1/2″ = 1′ 1:8
3″ = 1′ 1:4

Commonly Used Model Scales

Common scale factors used for models and hobbies
Scale Factor Model Type
1:4 steam trains, RC planes
1:8 steam trains, cars
1:10 figures
1:12 cars, motorcycles, dollhouses
1:16 steam trains, cars, motorcycles, military vehicles, figures
1:18 diecast cars
1:20 formula one cars
1:22.5 G-gauge trains
1:24 cars, trucks, aircraft, dollhouses
1:25 cars, trucks
1:32 1 gauge trains, cars, aircraft, figures
1:35 military vehicles
1:43 O-gauge trains, cars, trucks
1:48 O-gauge trains, dollhouses, Lego minifig
1:64 S-gauge trains, diecast cars, Hotwheels:Matchbox
1:72 aircraft, military vehicles, boats, cars
1:76 aircraft, military vehicles
1:87 HO-gauge trains, military vehicles
1:96 ships, spacecraft
1:100 aircraft, spacecraft
1:120 TT-gauge trains
1:144 ships, rockets, spacecraft
1:160 N-gauge trains, wargaming
1:200 aircraft, ships
1:220 Z-gauge trains
1:285 wargaming
1:350 ships
1:700 ships
1:720 ships