Scale Drawing Calculator
Type a length measured on the drawing, a scale like 1:50, the drawing unit, and the real unit. Real length in drawing units is drawn × (right / left). The page also converts into the real unit you pick. Not a survey plat.
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How to convert a scale drawing length
- Measure the drawn length on the paper or PDF. The default is 50.
- Type the scale as two positive numbers with a colon, such as 1:50.
- Pick the unit of that drawn measurement and the unit you want for the real world.
- Read the real length in the drawing unit and in the real unit. 50 mm at 1:50 is 2.5 m. Not a survey.
Representative fraction scale
Drawn × (b / a) for a scale a:b
| Scale syntax | a:b with both parts greater than 0 |
|---|---|
| Same-unit real | drawn × (b / a) |
| Default example | 50 mm at 1:50 is 2500 mm, which is 2.5 m |
| Drawing units | mm, cm, m, in, ft, km |
| Meter factors | mm 0.001, cm 0.01, m 1, in 0.0254, ft 0.3048, km 1000 |
| Advice | Map scale arithmetic. Not a survey. |
What a 1:50 scale means here
A representative fraction 1:50 means one unit on the drawing is 50 of the same units in the world. If you measured millimeters on paper, the first real length row stays in millimeters. The second row converts through meters into the real unit you picked. A unit converter without scale is the length page.
How real length is computed
Scale must match number:number. real_same = drawn × (b / a). real_meters = drawn × drawing_unit_in_meters × (b / a). Then divide by the real unit in meters. The default 50 mm × 50 = 2500 mm = 2.5 m. Both scale parts must be greater than 0.
RF, architect scales, and surveys
Architect scales such as 1/4 in = 1 ft are not this colon form unless you rewrite them as an RF. A recorded plat uses survey control, not a consumer ruler on a screenshot. Photocopy shrink is a second scale you would have to include yourself.
Use cases
A floor-plan takeoff from a 1:50 print, a map homework RF, or checking a PDF measure tool. Not a boundary survey.
Limits
Scale must look like 1:50. Drawn length must be greater than 0. Not a survey. CZNull does not receive the measures.