Question 1

What aspect ratio is 1920×1080?

Accepted Answer

1920×1080 is 16:9. The greatest common divisor of 1920 and 1080 is 120, so dividing both by 120 gives 16:9 (about 1.78:1) — the standard widescreen video and monitor ratio.

Question 2

How do I calculate the height for a given width at 16:9?

Accepted Answer

Height = width × 9 ÷ 16. For example a width of 1280px gives 720px, and 1000px gives 562.5px, which rounds to 563px (integer) or 562px (codec-safe even). Lock the ratio and type only the width to solve it automatically.

Question 3

What resolution are Instagram Reels and YouTube Shorts?

Accepted Answer

Reels, Shorts, and TikTok all use a vertical 9:16 ratio at 1080×1920. Instagram feed is 1:1 (1080×1080) or 4:5 portrait (1080×1350). YouTube video is 16:9 (1920×1080) and thumbnails are 1280×720.

Question 4

Why do video dimensions need to be even numbers?

Accepted Answer

Codecs such as H.264 and H.265 use 4:2:0 chroma subsampling, which requires even width and height to encode without errors. The even rounding mode snaps an odd derived value (e.g. 563) to the nearest even number (562).

Question 5

How do I resize while keeping the same aspect ratio?

Accepted Answer

Keep the ratio locked and change only the width or height — the other side is recalculated at the same ratio. Changing 16:9 from 1920 wide to 2560 wide, for instance, updates the height from 1080 to 1440.

Question 6

Is this aspect ratio calculator free and private?

Accepted Answer

Yes. It is completely free with no signup, and every calculation runs in your browser. Inputs are stored only in localStorage and the optional ?s= share link — nothing is sent to a server.

Aspect Ratio Calculator

Width : Height ratio

Pixel size

Result

Platform presets

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