AspectFit
Calculate dimensions

Common formats

Common aspect ratios

Start with 1:1, 4:3, 3:2, 16:9, or 9:16, then enter the target dimension you actually need.

Canonical server calculation

Dimensions

Numbers only — no upload
Ratio presets

Optional target size

Choose the side you know. The other side will be calculated.

Leave blank to reduce the ratio only.
The unrounded decimal value remains visible.