Aspect Ratio Calculator
Enter a width and height to find the simplified aspect ratio, plus the matching dimension for a new size.
Last updated: September 5, 2026
Frequently asked questions
How do I calculate an aspect ratio?
Divide both the width and height by their greatest common divisor (GCD) to simplify them to the smallest whole-number ratio - 1920×1080 simplifies to 16:9, since GCD(1920, 1080) = 120, and 1920÷120=16, 1080÷120=9.
How do I resize an image without distorting it?
Keep the same aspect ratio: pick your new width, then calculate the matching height using (new width × original height) ÷ original width - that's exactly what this calculator's "new width" field does.
What does a 'photo ratio' like 4:3 or 16:9 mean?
It's the proportional relationship between an image's width and height - 4:3 is a more square-ish traditional photo/TV shape, while 16:9 is the wider, more cinematic shape used by most modern screens and video.
What's the aspect ratio of a 1080×1920 vertical (portrait) video?
9:16 - the same ratio as 16:9 landscape video but rotated, since GCD(1080, 1920) = 120, giving 1080÷120=9 and 1920÷120=16.
Can I find the new width instead of the new height when resizing?
This calculator solves for a matching height given a new width; to go the other direction, swap the original width and height values you enter so the field effectively solves for the corresponding width instead.
What's the difference between aspect ratio and resolution?
Resolution (like 1920×1080) gives the exact pixel dimensions of an image, while aspect ratio (like 16:9) only describes the proportional shape - many different resolutions (1920×1080, 1280×720, 3840×2160) all share the same 16:9 aspect ratio.