Image Aspect Ratios Explained: 1:1, 4:3, 16:9 and More
By Ali Hamza · Published · 5 min read
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An image's aspect ratio is the relationship between its width and height, written as width:height. A 1:1 image is square; 4:3 is the classic camera and old-TV shape; 3:2 is the shape of most traditional camera sensors and 6 × 4 inch prints; 16:9 is widescreen video and most monitors; and 9:16 is the tall shape of phone stories and short videos. To change an image to a different ratio without making it look stretched, crop it to the new shape first, then resize it.
Reading a ratio
A ratio describes shape, not size. A 1200 × 800 image and a 3000 × 2000 image are both 3:2, because 1200 ÷ 800 = 3000 ÷ 2000 = 1.5.
To find an image's ratio, divide its width by its height:
| Width ÷ height | Ratio |
|---|---|
| 1.00 | 1:1 |
| 1.25 | 5:4 |
| 1.33 | 4:3 |
| 1.50 | 3:2 |
| 1.78 | 16:9 |
| 0.80 | 4:5 |
| 0.56 | 9:16 |
A value above 1 means landscape (wider than tall); below 1 means portrait.
Common ratios and where they are used
| Ratio | Shape | Typical use |
|---|---|---|
| 1:1 | Square | Profile pictures, product thumbnails, some social posts |
| 4:5 | Slightly tall | Portrait posts in social feeds |
| 3:2 | Landscape | Many camera sensors, 6 × 4 in prints |
| 4:3 | Landscape | Phone cameras' default photo mode, tablets, older screens |
| 16:9 | Wide | Video, monitors, TVs, presentations, website banners |
| 9:16 | Tall | Phone stories, short vertical videos, phone wallpapers |
| 1.91:1 | Wide | Link previews when sharing a web page (often 1200 × 630 px) |
| 7:9 | Tall | 35 × 45 mm passport photos |
Platforms change their recommended sizes from time to time, so check the platform's own help pages before a big campaign. The ratio matters more than the exact pixel count; most platforms resize images to fit their display.
What happens when the ratio does not match
If you put an image into a space with a different ratio, one of three things happens:
- Cropping: the platform cuts off the edges to fill the space. Your subject may lose the top of their head.
- Letterboxing: bars (often black or blurred) fill the gaps.
- Stretching: the image is forced into the new shape and looks distorted: faces wide or thin, circles become ovals.
Stretching is almost always the worst result. Cropping it yourself lets you choose what stays in the frame.
Changing the ratio without stretching
Step 1: Crop to the new ratio
Every phone and computer has a built-in crop tool with ratio presets:
- iPhone and Android: open the photo → Edit → Crop → choose the ratio (Square, 4:5, 16:9…).
- Windows Photos: Edit → Crop → Aspect ratio.
- Mac Preview: select an area while watching the size, then Tools → Crop.
Keep the important part, such as a face or a product, inside the frame, ideally following the "rule of thirds" (subject roughly a third of the way in, not dead centre) unless it is a portrait or product shot.
Step 2: Resize to exact pixels
Open the cropped image in the Image Resizer, keep Lock Aspect Ratio on, and type the width you need; the height follows automatically. Our guide on resizing an image to exact pixels covers this in detail.
A note on the resizer's ratio presets (1:1, 4:3, 16:9, 3:2): they set the output shape by stretching the whole image to fit, not by cropping. They are useful when your image is already very close to that ratio, or after you have cropped it. For anything else, crop first.
The alternative: add a border instead of cropping
Sometimes you cannot lose any of the image, for example with a document, a logo or a group photo. Instead of cropping, place the image on a canvas of the right shape with a plain or blurred border around it. Many phone editors and design apps have a "fit" or "border" option for this; social apps often offer it when you post a photo that does not match their shape.
A white or soft-grey border suits documents and product shots; a blurred, enlarged copy of the photo behind it suits pictures of people and places, because it fills the space without drawing attention.
Camera settings
Most phone cameras let you choose the ratio before you shoot, often 4:3 (the sensor's full area), 16:9 or 1:1. Shooting in 4:3 generally keeps the most pixels, because the other options crop the sensor. Choose 16:9 or 1:1 at shooting time only if you are sure of the final use, since you cannot add back what was cropped. When you shoot for an unknown purpose, leave some space around your subject so you can crop to several ratios later.
Ratios for print
Print sizes have their own ratios, which do not always match your photo:
| Print size | Ratio |
|---|---|
| 6 × 4 in (10 × 15 cm) | 3:2 |
| 7 × 5 in | 7:5 (1.4) |
| 10 × 8 in | 5:4 |
| A4 / A3 paper | about 1.41:1 |
| Square prints | 1:1 |
A 4:3 phone photo printed at 6 × 4 inches will be cropped slightly at the top and bottom or left and right. Crop it yourself first to control what is lost. For prints at a fixed physical size, see image DPI explained, and for passport photos, which have strict head-size rules within the ratio, use the Passport Photo Maker.
Frequently asked questions
What aspect ratio is 1920 × 1080?
16:9. Divide 1920 by 1080 to get 1.78, the 16:9 ratio.
What is the best aspect ratio for a social media post?
It depends on the platform and placement. Square (1:1) and slightly tall (4:5) are common for feeds; 9:16 for stories.
Does changing the aspect ratio reduce quality?
Cropping removes pixels, so the image becomes smaller, but the remaining area keeps its quality. Stretching distorts it.
How do I make a photo square without cropping?
Place it on a square background with borders, rather than cropping or stretching.
Is my image uploaded when I resize it?
No. ToolMany's Image Resizer works in your browser.
