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Drawing Scale Chart
A drawing scale tells you how much real distance each unit on the paper stands for. On a 1/4 inch scale floor plan, 1/4 inch on the page is one foot in the house. The charts below list every common scale with its ratio and what it is used for, and each links to a full conversion chart.
Architectural scales
Used on floor plans, elevations, and details in the U.S. Each one says how much paper stands for one real foot.
| Scale | Ratio | 1 inch on paper | Used for |
|---|---|---|---|
| 1/16" = 1'-0" | 1:192 | 16' | overall plans of large buildings and key plans that show a whole floor on one sheet |
| 3/32" = 1'-0" | 1:128 | 10' 8" | large floor plans and overall plans when 1/8 inch scale will not fit the sheet |
| 1/8" = 1'-0" | 1:96 | 8' | floor plans of larger homes and commercial buildings |
| 3/16" = 1'-0" | 1:64 | 5' 4" | floor plans and elevations when a 1/4 inch plan is too big for the sheet |
| 1/4" = 1'-0" | 1:48 | 4' | residential floor plans and exterior elevations |
| 3/8" = 1'-0" | 1:32 | 2' 8" | enlarged plans of rooms such as kitchens and bathrooms |
| 1/2" = 1'-0" | 1:24 | 2' | enlarged plans |
| 3/4" = 1'-0" | 1:16 | 1' 4" | wall sections and larger construction details |
| 1" = 1'-0" | 1:12 | 1' | construction details such as stair sections |
| 1-1/2" = 1'-0" | 1:8 | 8" | construction details that need to show individual boards |
| 3" = 1'-0" | 1:4 | 4" | full construction details such as millwork |
Engineering scales
Used on site plans, surveys, and civil drawings. Each one says how many real feet one paper inch stands for.
| Scale | Ratio | 1 inch on paper | Used for |
|---|---|---|---|
| 1" = 10' | 1:120 | 10' | site plans for single lots |
| 1" = 20' | 1:240 | 20' | site plans for residential and small commercial lots |
| 1" = 30' | 1:360 | 30' | site plans for larger lots and small commercial developments |
| 1" = 40' | 1:480 | 40' | civil site plans |
| 1" = 50' | 1:600 | 50' | subdivision plans and site plans for large commercial properties |
| 1" = 60' | 1:720 | 60' | subdivision plats |
| 1" = 100' | 1:1200 | 100' | overall site plans |
Metric scales
Used on drawings almost everywhere outside the U.S. A ratio like 1:50 means one unit on paper is 50 of the same unit in real life.
| Scale | 1 cm on paper | Used for |
|---|---|---|
| 1:20 | 20 cm | construction details |
| 1:25 | 25 cm | details |
| 1:50 | 50 cm | house floor plans |
| 1:100 | 1 m | floor plans and elevations of larger buildings |
| 1:200 | 2 m | building plans of large projects and site plans of smaller sites |
| 1:500 | 5 m | site plans and block plans that show a building on its plot |
| 1:1000 | 10 m | location plans and maps that show a site in its surroundings |
Measuring a plan without a scale ruler
The floor plan scale calculator converts between paper and real measurements for any scale. To see what the measurements mean for a room, the room size chart and the square footage chart put common sizes in context.
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