Metric Scale Calculator
Convert real-world metric dimensions to plotted paper measurements—or paper measurements back to real dimensions—at any 1:N CAD scale.
Enter your values, then select Calculate.
Runs in your browser. No calculation data is sent to an external service.
What this calculator does
This is the fastest way to answer questions such as “How long should 25 m measure on paper at 1:100?” or “What real distance does 80 mm represent at 1:50?”
Example
At 1:100, a real 25 m length becomes 250 mm on paper. In reverse, 80 mm measured on a 1:50 sheet represents 4,000 mm, or 4 m, in the real world.
How to use the result
- For a prepared Layout, keep the sheet itself at 1:1 and use the viewport to control model scale.
- Use millimetres when checking printed distances with a physical ruler.
- Never use Fit to Paper on a scale-critical issue sheet.
Frequently asked questions
How do I calculate paper length at 1:50?
Convert the real dimension to the same base unit and divide it by 50.
Does 1:100 mean 1 mm equals 100 mm?
Yes. The ratio is unitless: 1 mm on paper represents 100 mm in reality, just as 1 cm represents 100 cm.
Can I use this for Civil 3D sheets?
Yes. The scale math is the same; Civil 3D may add production-view and profile considerations around that basic relationship.
Explore more in CAD Plotting Tools & Calculators.