Ratio & Resize Calculator
Enter the original size, then type a target width or height - or pick a percentage. The other dimension updates automatically and the aspect ratio is shown.
Original size
Aspect ratio
-
-
Resize by dimension
Quick %
75%
- × -
50%
- × -
25%
- × -
- × -
How it works
The tool preserves the aspect ratio. When you type a new width it calculates height as height = width × (original height ÷ original width) - and vice versa.
Percentages are applied to both width and height at the same time.
- Toggle rounding if you prefer whole-pixel results.
- Share a pre-filled link using
?w=WIDTH&h=HEIGHT&p=PERCENT.
Example: 1920 × 1080 → 50% = 960 × 540