Common aspect ratios and where each one is used

Seven ratios cover nearly everything you will shoot, design or watch. Here is what each one is for, its standard pixel sizes, and what happens when you switch between them.

Updated 9 October 2026 · 6 min read

The common aspect ratios at a glance

The decimal value is simply width ÷ height. Anything above 1 is landscape, below 1 is portrait, and exactly 1 is square.

To scale any size while keeping its ratio, use the aspect ratio calculator: type the original size, then the new width or height.

16:9: video and screens

16:9 (1.78) became the standard for HD and 4K television and is now the shape of most monitors, laptops in video mode, YouTube videos and presentation templates. Every common 16:9 resolution is a multiple of 16 × 9: 1920 × 1080 is 120 times, 3840 × 2160 is 240 times. If you need a custom size, pick a width that is a multiple of 16 and the height comes out as a whole number.

4:3: phone photos and older screens

4:3 (1.33) was the shape of standard-definition TV and early computer monitors. It is still the default photo shape on most phone cameras, which is why phone photos look "boxy" next to 16:9 video and get black bars or cropping when shown full-screen on a TV. Many tablets also have screens at or close to 4:3.

3:2: cameras and classic prints

3:2 (1.5) comes from 35 mm film (36 × 24 mm) and carried over to most DSLR and mirrorless cameras. It is also exactly the shape of a 4 × 6 inch print (and 10 × 15 cm), so camera photos print at that size without cropping.

1:1 and 4:5: feed posts

Square 1:1 is the safe choice for profile pictures and thumbnails, because most apps crop avatars to a square or circle. Portrait 4:5 (1080 × 1350) has long been the standard portrait size for Instagram feed posts, and it takes up more of the screen than a square. 4:5 is also exactly the proportion of an 8 × 10 inch print. Platform specs change from time to time, so check the platform's help pages before a big campaign.

9:16: vertical video

9:16 is 16:9 turned on its side: 1080 × 1920 is the usual size for Stories, Reels, TikTok and YouTube Shorts. Keep text and faces away from the top and bottom edges, where apps place their own buttons and captions. Modern phone screens are taller than 9:16 (often around 19.5:9 or 20:9), so a 9:16 video may show thin bars or be slightly zoomed in.

21:9: ultrawide and cinema

"21:9" is a marketing name rather than an exact ratio. Real ultrawide monitors are 2560 × 1080 (2.37) or 3440 × 1440 (2.39), and many cinema films are 2.39:1. A 21:9 video on a 16:9 screen shows black bars above and below; a 16:9 video on a 21:9 monitor shows bars on the sides.

Other ratios you will meet

• 16:10 (1.6): many laptops and some monitors, e.g. 1920 × 1200 and 2560 × 1600.
• 5:4 (1.25): old 1280 × 1024 monitors, and 8 × 10 prints in landscape.
• 1.85:1 and 2.39:1: the two common cinema formats, "flat" and "scope".
• 1:√2 (1:1.414): every A-series paper size. See the A paper sizes chart.

How to work out the ratio of any size

1. Find the greatest common divisor of width and height. For 1920 × 1080 it is 120.
2. Divide both by it: 1920 ÷ 120 = 16, 1080 ÷ 120 = 9, so 16:9.
3. If the numbers come out large and odd (for example 2560 × 1080 gives 64:27), the size is not one of the standard ratios. Use the decimal (2.37) to compare it with others.

Changing ratio means cropping or bars

You cannot turn one ratio into another without losing something. Either you crop part of the picture, add bars (letterboxing or pillarboxing), or stretch it, which distorts faces and circles and should be avoided. How much you lose by cropping:

If you know a photo will end up in several shapes, frame the subject loosely in the middle when you take it, so every crop still works. For the exact new dimensions at any size, the calculator keeps the ratio locked, and the DPI calculator tells you whether a cropped photo still has enough pixels to print.

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