Scale Conversion Calculator
Convert scale to actual size, actual to scale, or find the scale factor. 12 preset architectural, engineering, and model scales plus custom ratio.
πΊοΈ Scale Conversion Calculator
RESULTS
π‘ How to Use Scale Conversions
Scale conversion translates measurements between drawings, blueprints, models, and real-world dimensions. The calculator supports 3 modes and 12 preset scales used in US architecture, engineering, and model building. For converting the resulting dimensions, use our feet and inches calculator or inch fraction calculator.
Three Calculation Modes
- Scale β Actual Size: Enter the measurement from a drawing or model, select the scale ratio, and get the real-world dimension in inches, feet, and meters.
- Actual β Scale Size: Enter the real dimension, select scale ratio, and find the drawing/model measurement in inches.
- Find Scale Factor: Enter both the scale measurement and actual measurement to determine the scale ratio (1:X).
Architectural Scales
Used on US residential and commercial blueprints. The fraction of an inch on the drawing equals one foot in reality.
| Scale Notation | Ratio | 1" on Drawing = | Common Use |
|---|---|---|---|
| 1" = 1' | 1:12 | 1 foot | Detail drawings, millwork |
| 1/2" = 1' | 1:24 | 2 feet | Interior details, cabinets |
| 1/4" = 1' | 1:48 | 4 feet | Residential floor plans |
| 1/8" = 1' | 1:96 | 8 feet | Small residential, elevations |
| 1/16" = 1' | 1:192 | 16 feet | Site plans, large buildings |
Engineering Scales
Used on US civil and site engineering drawings. One inch on the drawing equals a specific number of feet.
| Scale Notation | Ratio | 1" on Drawing = | Common Use |
|---|---|---|---|
| 1" = 10' | 1:120 | 10 feet | Plot plans, details |
| 1" = 20' | 1:240 | 20 feet | Site plans, grading |
| 1" = 30' | 1:360 | 30 feet | Road profiles |
| 1" = 40' | 1:480 | 40 feet | Subdivision plans |
| 1" = 50' | 1:600 | 50 feet | City planning, civil |
Common Model Scales
| Scale | Ratio | 1" Model = | Common Use |
|---|---|---|---|
| 1:12 | 1:12 | 1 foot | Dollhouses, large models |
| 1:18 | 1:18 | 1.5 feet | Large diecast cars |
| 1:24 | 1:24 | 2 feet | Model cars, aircraft |
| 1:43 | 1:43 | 3.58 feet | O Gauge trains, diecast |
| 1:64 | 1:64 | 5.33 feet | Hot Wheels, S Gauge |
| 1:87 | 1:87 | 7.25 feet | HO Scale (most popular) |
| 1:160 | 1:160 | 13.33 feet | N Scale trains |
| 1:220 | 1:220 | 18.33 feet | Z Scale trains |
How to Find the Scale Factor
Scale factor = actual size Γ· model size
Measure both the model/drawing and the real object in the same unit. Divide actual by model. Example: a doorway is 80" tall in reality and 1.67" on the model. 80 Γ· 1.67 = 1:48 (which is 1/4" = 1' architectural scale).