Proportion Calculator
Scale any drawing up or down while keeping proportions identical. Get scale factor and exact new dimensions.
Original Size
Target Size
What Is a Proportion Calculator for Artists?
When moving from a small sketch to a large canvas — or reducing a reference to fit your paper — you need a consistent scale factor. This calculator gives you exact new dimensions instantly.
Enter your original width and height, then specify a target width or height. The tool calculates the scale factor, percentage change, and final dimensions.
Scaling artwork proportionally prevents distorted faces, stretched horizons, and uneven grid cells. Use the scale factor to match your reference grid to any canvas size before you start drawing.
When to Use a Drawing Scale Calculator
- Exact Scale Factor
Know precisely how much larger or smaller your work becomes.
- Two-Way Input
Scale by target width or height — whichever you know first.
Related Tools
How to Scale Artwork Proportionally
Enter Original Size
Input your reference or sketch dimensions.
Set Target Dimension
Enter desired width or height to scale to.
Apply Scale Factor
Use the calculated dimensions for your final artwork.
Proportion Calculator FAQ
How is this different from the aspect ratio calculator?+
The proportion calculator focuses on scaling — it gives you a scale factor and new dimensions from a target size.
Can I scale down?+
Yes. Enter a target smaller than the original and the tool calculates the reduced dimensions.
When do artists need a proportion calculator?+
Use it when enlarging a sketch to canvas, shrinking a reference to fit your paper, or matching grid cell sizes across different surface dimensions.
Does scaling change aspect ratio?+
No. This calculator scales proportionally — width and height change by the same factor so your drawing stays undistorted.