Reduces any width and height into their simplest ratio form — the standard way photo, video, and screen resolutions are described.
How it works
The greatest common divisor of the width and height is found, then both numbers are divided by it to give the simplest equivalent ratio.
What this does not include
This does not include converting between specific resolutions of the same ratio — this calculator specifically reduces a given width and height to its simplest ratio form.
How to use this calculator
- Enter the width and height (in pixels, inches, or any consistent unit).
A worked example
1920 × 1080 pixels: greatest common divisor simplifies this to 16:9 — standard widescreen.
4096 × 2160 pixels (DCI 4K): simplifies to 256:135 — a non-round ratio, since this cinema standard doesn’t reduce to a clean fraction like 16:9 does.
What the variables mean
| Variable | Meaning |
|---|---|
| Width, height | Dimensions in pixels (or any consistent unit) |
Edge cases worth knowing
Not every resolution reduces to a familiar ratio. The DCI 4K example above shows a real, correctly simplified ratio that just doesn’t happen to match a common named standard like 16:9 or 4:3.
A width or height of zero makes the ratio meaningless — there’s no valid rectangle with a zero dimension, so the calculator declines to show a result.
Frequently asked questions
Why is 1920×1080 the same ratio as 16:9?
Because 1920 and 1080 share a greatest common divisor of 120 — dividing both by it gives exactly 16 and 9.
Does the unit of measurement matter?
No — the ratio is the same whether width and height are measured in pixels, inches, or centimeters, as long as both use the same unit.
What’s a common use for this calculator?
Checking whether a photo, video, or screen resolution matches a standard ratio like 16:9 or 4:3 before cropping or resizing.
