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Aspect Ratio Calculator

Resize an image/video resolution while keeping aspect ratio. Convert to presets like 16:9, 4:3, 1:1, 9:16. Local-only.

Input

Enter original size, pick a target ratio, then lock width or height.
Tip: If you must upload to a platform that requires a fixed ratio (e.g., 4:3), resizing preserves the full image, while cropping changes the framing.

How to use

1) Enter original

Type your original width and height (e.g., 1920×1080).

2) Choose ratio

Select a preset ratio (16:9, 4:3, 1:1) or enter a custom ratio.

3) Lock width/height

Lock by width or height and enter the new value to calculate the other side.

What this tool does

An aspect ratio is width:height. When you resize while preserving aspect ratio, the image keeps its shape (no stretching). This tool calculates the matching dimension so you can export a correct resolution.

If you need an exact target ratio but your original doesn’t match, you have two options: resize (keeps everything, changes pixel size) or crop (cuts edges to fit).

FAQ