Scale Conversion Calculator – Convert Measurements to a Scaled Size

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

Find the Scaled Size

Scale Factor: :

Find the Scale Factor

Scaled Results:

Scale Factor: 1:8
Scaled Size: 4 ft


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 can be used 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 = 32 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 it will need to be reduced to 1:n. Use our ratio calculator to reduce a ratio. A ratio can also be reduced by dividing both the numerator and the denominator by the numerator.

For example, 2/3 can be reduced 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
1:20 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 cars, trucks
1:48 O-gauge trains, dollhouses, Lego minifig
1:64 S-gauge trains, die-cast cars, Hotwheels:Matchbox
1:72 aircraft, military vehicles, boats
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