Aspect Ratios Explained: 1:1, 4:5, 16:9 and 9:16, and How to Crop to Each

What an aspect ratio is

An aspect ratio compares the width of a picture with its height. A ratio of 16:9 means that for every 16 units of width there are 9 units of height. The units can be pixels, millimetres or inches, because only the proportion matters.

Two pictures with different sizes can have the same ratio. A picture of 1920 × 1080 pixels and a picture of 1280 × 720 pixels are both 16:9, and one is simply bigger than the other. This is why the ratio tells you about the shape and nothing about how sharp the picture is.

The shapes you will meet most often

Apps and websites change their preferred sizes from time to time, so check their help pages when a detail matters. These are the common shapes and what they are used for:

• 1:1 is a square. It is used for profile pictures and many feed posts.
• 4:5 is a slightly tall portrait. It is popular for portrait posts, because it fills more of a phone screen than a square does.
• 3:4 and 2:3 are taller portrait shapes. 3:4 is what many phone photos have when the phone is held upright, and 2:3 is the shape of portrait prints and posters.
• 4:3 and 3:2 are the shapes of many camera photos. Many phones shoot 4:3 and many cameras shoot 3:2, though it depends on the device and its settings.
• 16:9 is the widescreen shape of most monitors, televisions and online video, and of many slides and thumbnails.
• 9:16 is 16:9 turned on its side. It is the shape of a phone screen held upright and is used for stories, reels and short videos.

How to work out the other side

If you know the width and the ratio, you can work out the height. Multiply the width by the second number of the ratio and divide by the first number. Some examples:

• A width of 1080 pixels at 4:5 gives a height of 1080 × 5 ÷ 4 = 1350 pixels.
• A width of 1920 pixels at 16:9 gives a height of 1920 × 9 ÷ 16 = 1080 pixels.
• A width of 1080 pixels at 9:16 gives a height of 1080 × 16 ÷ 9 = 1920 pixels.
• A width of 1080 pixels at 1:1 gives a height of 1080 pixels.

How much of your photo you keep

When you change the shape of a photo by cropping, you keep the largest area of the new shape that fits inside the photo, and the rest is cut off. How much you keep depends on how different the two shapes are.

• A landscape photo of 4000 × 3000 pixels gives a 1:1 crop of 3000 × 3000, a 4:5 crop of 2400 × 3000, a 16:9 crop of 4000 × 2250 and a 9:16 crop of about 1688 × 3000.
• A portrait photo of 3000 × 4000 pixels gives a 4:5 crop of 3000 × 3750 and a 1:1 crop of 3000 × 3000. A 16:9 crop of the same photo is only 3000 × 1688.
• A photo loses the most when its shape is far from the shape you want, for example a tall portrait cropped to wide 16:9. Then it is often better to choose a different photo than to crop a thin strip.

Crop, add bars or stretch

There are three ways to make a picture fit a shape that it does not have. For photos, cropping is usually the best choice. For a slide or a document where nothing may be cut off, adding a background is safer.

• Crop: cut away what does not fit. The picture stays natural, but you lose the edges.
• Add bars or a background: keep the whole picture and fill the empty space with a colour. Nothing is lost, but the picture is smaller inside the frame.
• Stretch: squeeze or pull the picture to fill the frame. Faces and round objects look wrong, so avoid this for photos.

Shape is not sharpness

The ratio gives the shape and the resolution gives the sharpness. A 16:9 crop that is only 640 × 360 pixels has the right shape and will look soft on a large screen. Making a small picture bigger cannot add detail that was never there.

So check two things: that the shape is right, and that the crop has enough pixels for the size you need. A good tool shows the size of the crop in pixels before you save it.

A simple order of steps

1. Find the ratio and the size in pixels in the instructions of the place where the picture will be used.
2. Start from your original photo, not from a screenshot or a copy that was already compressed.
3. Rotate the photo upright if it is sideways.
4. Crop to the ratio and move the frame so that the subject sits in the middle with some room around it.
5. Set the final size in pixels, for example a width of 1080.
6. Save as JPG for photos, then look at the result at full size.

Doing it on this site

The Crop Image tool on GetTaskCraft has the common shapes ready, including 1:1, 4:5, 16:9 and 9:16, together with a custom ratio and rotate and flip buttons. Resize Image can add a background around a picture instead of cropping it. Both run in your browser, so your pictures are not uploaded to a server.