# Scale Converter

> scale converter that translates measurements between model scales like 1:24, 1:48, 1:87 and real-world sizes in inches, mm, and feet. Free, runs in your browser.

- **Canonical URL:** https://boringtoolskit.com/scale-converter/
- **Category:** Converters
- **Evidence level:** authored-methodology
- **Reviewed:** July 26, 2026
- **Last verified:** 2026-10-12
- **Privacy:** Inputs and results stay in this browser unless the page clearly labels an external request.

## How it works

Multiply the length you measure on the drawing by the scale ratio to get the real size. A 1:N scale means 1 unit on paper equals N of the same units in reality. If you measured in centimeters, the result is divided by 100 to show meters.

## Worked example

A room measures 4.2 cm on a 1:100 floor plan. Real size = 4.2 × 100 = 420 cm = 4.20 m.

## Assumptions

- The ratio is the denominator of a 1:N scale, so a 1:100 plan uses ratio 100.
- The measured length is a straight-line distance on the drawing, entered in centimeters or meters.
- The drawing is printed at its stated scale; enlarging, shrinking, or photocopying it invalidates the ratio.

## Common questions

### What does a scale of 1:100 mean?

One unit on the drawing equals 100 of the same units in real life. A 1 cm line on a 1:100 plan represents 100 cm, or 1 m, at full size.

### How do I read a measurement from a 1:50 blueprint?

Multiply the length you measure by 50. A 9 cm pipe run on a 1:50 drawing is 9 × 50 = 450 cm, or 4.50 m in reality.

### Which scales do plans, site plans, and maps use?

Detailed building plans commonly use 1:20 to 1:100, site plans use 1:200 to 1:500, and maps use 1:25,000 or larger ratios such as 1:50,000.

## Related tools

- /length-converter/
- /aspect-ratio-calculator/

## Sources

- [Calculation methodology and reference cases](https://boringtoolskit.com/methodology/)
- [Architectural drawing](https://en.wikipedia.org/wiki/Architectural_drawing)
- [Scale ruler](https://en.wikipedia.org/wiki/Scale_ruler)

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