Aspect Ratio Calculator
Resize media without distortion. Enter the original width and height once, then set either a new width or a new height and the matching side is recalculated instantly. This page is for preserving a photo or video frame while scaling it, not for turning a screen diagonal into dimensions like the Screen Size calculator.
Examples
1920 × 1080 to 800 px wide
A standard landscape frame scaled down without changing shape.
- Original width
- 1,920 px
- Original height
- 1,080 px
- New width
- 800 px
Matching side
450 px
Resized width
800 px
Resized height
450 px
Reduced ratio
16:9
Decimal ratio
1.778
Examples
How It Works
Formula
Variables
- Original width(px)
- Original height(px)
- New width(px)
- New height(px)
- Source aspect ratio (original width divided by original height)
The calculator first reads the source ratio as width divided by height. Then it treats either the new width or the new height as the driver and recomputes the other side so the ratio stays unchanged.
Frequently Asked Questions
01What does aspect ratio mean here?
Aspect ratio is the relationship between width and height. A frame that is 1920 by 1080 has a 16:9 ratio, which means every resize has to keep the same proportion if you want the image or video to stay undistorted.
02Why does the other side change automatically?
Because only one target side should drive the resize at a time. When you lock a new width, the matching height is width divided by the source ratio. When you lock a new height, the matching width is height multiplied by the source ratio.
03Why might I see an exact ratio like 683:384 plus an approximate 16:9 hint?
Some real source sizes reduce to awkward but perfectly correct integer ratios. The calculator keeps the true reduced ratio visible, then adds a nearby common-ratio hint only as a reference. It never snaps your media to that hint.
04How is this different from the Screen Size calculator?
Screen Size starts with a display diagonal and an aspect ratio, then solves for width and height. This calculator starts with a real width and height that already exist and helps you resize the media without changing its shape.