Scale Conversion Calculator

Enter your Real Size, choose its unit, then set your Scale Numerator and Denominator to get the exact Scale Size — plus a handy Scale Factor and Scale Ratio so you always know how your model, map, or drawing relates to the real thing.

First number in scale ratio (e.g., 1 in 1:24)

Second number in scale ratio (e.g., 24 in 1:24)

Results

Scale Size

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Scale Factor

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Scale Ratio

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Frequently Asked Questions

What is a scale factor?

A scale factor is the ratio that describes how much a drawing or model has been enlarged or reduced compared to the actual object. It's calculated by dividing the scaled size by the real size.

How do you calculate scale from a drawing?

To calculate scale from a drawing, measure a known dimension on the drawing and divide it by the actual real-world dimension. This gives you the scale factor, which can then be expressed as a ratio.

Is scale factor always greater than 1?

No, scale factor can be greater than, less than, or equal to 1. If it's greater than 1, the scale drawing is larger than the actual object. If less than 1, the drawing is smaller than the actual object.

What is an example of a scale factor?

A common example is architectural drawings at 1:100 scale, meaning 1 unit on the drawing represents 100 units in real life. So a 1cm line on the drawing represents 100cm (1 meter) in reality.

How do I convert between different scale ratios?

To convert between scales, first calculate the actual real-world size from your current scale, then apply the new scale factor to get the measurement in the target scale.

What scales are commonly used in architecture?

Common architectural scales include 1:100, 1:50, 1:20 for floor plans, and 1:500 or 1:1000 for site plans. The choice depends on the level of detail needed and drawing size constraints.

Can I use this calculator for model trains and cars?

Yes! This calculator works perfectly for model scales. Popular model train scales include HO (1:87), N (1:160), and O (1:48). Model car scales include 1:18, 1:24, and 1:64.

How accurate are the scale conversions?

The calculator provides highly accurate conversions with precision up to 4 decimal places. However, always consider manufacturing tolerances and measurement precision in real-world applications.

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