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Aspect ratio calculator

Find the aspect ratio of a resolution, resize while keeping it, and see common sizes for 16:9, vertical 9:16, Instagram 4:5 and cinema widescreen.

  • Free, no limits
  • No sign-up
  • Even sizes for video

Size and ratio

Aspect ratio
16:9
As a number
1.778:1
Common use
HD and 4K video, YouTube

Resize to the same ratio

Most video codecs need even widths and heights.

New height
720
New size
1280 × 720
Common widths at this ratio
640 ×360
1280 ×720
1920 ×1080
2560 ×1440
3840 ×2160

FAQ

Frequently asked questions

Something else, or a file that will not convert? Write to conform@niamori.ai.

How do I calculate an aspect ratio?

Divide the width and height by their greatest common divisor: 1920 × 1080 divided by 120 is 16:9. Some screens are not exact, such as 1366 × 768, which is 683:384 but close enough to 16:9 to be called that.

What is the difference between 2.39:1 and 21:9?

2.39:1 is the anamorphic cinema scope ratio used in theatrical releases. 21:9 is a marketing name for ultrawide monitors and is really about 2.37:1 (2560 × 1080) or 2.39:1 (3440 × 1440), so the two are close but not the same.

Why round to even numbers?

H.264, HEVC and most other video codecs store color at half resolution, so widths and heights must be divisible by two. An odd size makes the export fail or adds a line of padding.

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