Aspect ratio calculator for images

Find the width-to-height ratio and calculate a new dimension while keeping proportions. No image upload required.

Result

Enter your values to see the result.

Download result

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How to use it

Choose the destination frame first. Resize when the ratios match to keep the whole photo. Crop to fill a different-shaped frame by removing part of the picture. Add borders to retain the full composition within that frame.

Example inputs
Input	Result
1920 × 1080 px; 1280 px	16:9; 1280 × 720 px

Method and limits

Height is rounded to the nearest pixel, so the resulting ratio may differ slightly. The image file is not changed.

Example

Usage scenario

Input: 1920 × 1080 px; 1280 px
Result: $\frac{1280 \times 9}{16} = 720$

Calculation steps

Reduce the ratio width
$\frac{1920}{120} = 16$
Reduce the ratio height
$\frac{1080}{120} = 9$
Calculate the new height
$\frac{1280 \times 9}{16} = 720$

A 1920 × 1080 image reduces to 16:9 by dividing both dimensions by 120. To make it 1280 pixels wide, apply the same scale factor to the height: the result is 720 pixels.

What are the limits of this tool?

Whole-pixel dimensions from 1 to 1,000,000. The final height is rounded; the file is not modified.

Inputs and results are processed in your browser and are not sent to the server. Aggregate statistics, when enabled, record only the tool and outcome, without the content.

Sources

MDN — aspect-ratio

PRACTICAL GUIDES

4:3 vs 16:9: choosing an image aspect ratio

Separate aspect ratio from resolution. Learn when to resize, crop or add borders while keeping a photo’s proportions.

Follow the steps

Aspect ratio calculator for images

Set your data

Result

How to use it

Method and limits

Example

Usage scenario

Calculation steps

What are the limits of this tool?

Sources

4:3 vs 16:9: choosing an image aspect ratio

Favorites

Aspect ratio calculator for images

Set your data

Result

How to use it

Method and limits

Example

Usage scenario

Calculation steps

What are the limits of this tool?

Sources

4:3 vs 16:9: choosing an image aspect ratio

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