Aspect Ratio

Calculate missing width or height from any aspect ratio. Supports 16:9, 4:3, 1:1, 9:16, 21:9, and custom ratios. Free, no signup.

Runs entirely in your browser — files never uploaded

16:9aspect ratio

Width (px)

Height (px)

Presets

Total pixels

2,073,600

Megapixels

2.07 MP

Proportional preview

1920 × 1080

How to use Aspect Ratio

1. Enter dimensions. Type a width and height in pixels. The aspect ratio is calculated automatically.
2. Lock a dimension. Lock either width or height. When you change the other value, the locked one recalculates to keep the ratio.
3. Use a preset. Click a common ratio like 16:9, 4:3, or 1:1 to snap your dimensions to that proportion.
4. Read the stats. See total pixel count, megapixels, and a proportional preview rectangle.

What is an aspect ratio?

An aspect ratio is the proportional relationship between width and height. 16:9 means for every 16 units wide, the image is 9 units tall.

How does the lock work?

When 'Height' is locked, changing the width recalculates the height to maintain the current ratio. When 'Width' is locked, the opposite happens.

Can I enter custom aspect ratios?

Yes — just type any width and height. The tool simplifies the ratio automatically (e.g. 1920×1080 → 16:9).

What are megapixels?

Megapixels = width × height ÷ 1,000,000. A 1920×1080 image is about 2.07 megapixels.