Scale & Resize Calculator
Calculate exact dimensions when resizing images, prints, or designs by percentage.
Scaling Math: Area Changes Faster Than You Think
When you scale a 2D image by a percentage, the area changes by the square of that percentage. Scaling to 50% doesn't give you 50% of the area — it gives you only 25%.
This is why reducing image dimensions by "just 10%" actually reduces the file size by roughly 19% (0.9 × 0.9 = 0.81 = 81% of original area).
Common Paper Size Scaling
| From | To | Scale |
|---|---|---|
| A3 (297×420) | A4 (210×297) | 70.7% |
| A4 (210×297) | A5 (148×210) | 70.7% |
| Letter (8.5×11) | A4 (210×297) | 97% width |
| A4 | Letter | 103% width |
| A4 | A3 | 141.4% |
| Tabloid (11×17) | Letter (8.5×11) | 64.7% |
Each A-series paper step is exactly √2 ≈ 141.4% (or 70.7% to go smaller). This elegant system was designed so that any A-size document scales perfectly to the next size.
Material Waste Calculation
Designers often add 10% extra material for cutting waste, bleed, and mistakes. On a 1,000 sq ft project, 10% waste = 100 sq ft extra. This "10% off the top" can mean the difference between running out of material and completing the job.