Photo aspect ratios explained: 1:1, 4:5, 4:3, 3:2, 16:9, 9:16
An aspect ratio is the width of a picture divided by its height, written as two numbers: 4:5 is four units wide for every five units tall. Each common ratio comes from a real source, such as a camera sensor, a film frame, a print paper size or a screen. When a form or app wants a particular ratio, you have two choices. You can crop the picture to that shape, which removes pixels at the edges, or pad it, which keeps every pixel and adds a border. Choose by whether the subject can afford to lose its edges.
Crop imageNeeds to be squareOpenWhere the common shapes come from
| Ratio | Where you meet it | Origin |
|---|---|---|
| 1:1 | Square profile pictures and square grid posts | Medium-format 6 × 6 cm film frames are square |
| 4:5 | Portrait posts, and 8 × 10 in prints | 8 × 10 in is 4:5, and so is 4 × 5 in large-format film |
| 4:3 | Many phone photos and compact cameras | A common sensor shape, and the old television standard |
| 3:2 | DSLR and mirrorless cameras, 4 × 6 in prints | A 35 mm film frame is 36 × 24 mm, which is 3:2 |
| 16:9 | HD video, widescreen TVs and monitors | 1920 × 1080 pixels is 16:9 |
| 9:16 | Phone screens held upright, vertical video | The 16:9 frame turned on its side |
Many phone cameras capture photos at 4:3 by default and video at 16:9. A phone picture therefore usually needs a crop before it fits a 1:1, 4:5 or 9:16 frame.
Same shape, different sizes
A ratio describes shape, not size. 4:5 covers 1080 × 1350 pixels, 2160 × 2700 pixels and any other pair in the same proportion. The check is simple: a width of 1080 at 4:5 gives a height of 1080 ÷ 4 × 5, which is 1350.
| Ratio | Pixels | Check |
|---|---|---|
| 1:1 | 1080 × 1080 | Equal sides |
| 4:5 | 1080 × 1350 | 1080 ÷ 4 × 5 = 1350 |
| 9:16 | 1080 × 1920 | 1080 ÷ 9 × 16 = 1920 |
| 16:9 | 1920 × 1080 | 1920 ÷ 16 × 9 = 1080 |
| 3:2 | 1800 × 1200 | 1800 ÷ 3 × 2 = 1200 |
To measure a photo's ratio, divide its width by its height. A 4000 × 3000 photo gives 1.333, which is 4:3. A 1080 × 1350 frame gives 0.8, which is 4:5.
Crop or pad
Cropping keeps the pixels inside a frame and discards the rest. Padding keeps every pixel and adds a border, so nothing is cut. Stretching changes the shape without keeping proportions, which distorts people and objects, so avoid it.
Cropping costs more than it looks. A 4000 × 3000 photo cropped to 4:5 keeps a 2400 × 3000 frame, so 40 per cent of the width is gone. Cropped to 16:9, it keeps 4000 × 2250, so a quarter of the height goes. Check whether the subject survives before you commit.
Before you drag a frame, decide what must stay inside it. For a portrait, keep the eyes and the top of the head with some room above. For a product, keep the whole outline, including any label or handle. If the must-keep area is larger than the frame, no crop can hold it, and padding is the only way to keep everything.
Padding suits photos where the edges matter, such as a group, a product or a document. The square tool fits the whole picture into a 1:1, 4:5, 9:16 or 16:9 frame, with a blurred, white, black or custom border.
A worked crop
Take a 6000 × 4000 landscape photo, which is 3:2. Cropped to 4:5 with the height kept at 4000, the width must be 4000 ÷ 5 × 4, which is 3200. The frame is 3200 × 4000, so 2800 pixels of width are cut, or 46.7 per cent of the photo. The same photo cropped to 9:16 needs a width of 4000 ÷ 16 × 9, which is 2250, so 3750 pixels, or 62.5 per cent of the width, go. Numbers like these show why a tall crop suits a subject near the centre and not a subject at the edge.
The steps
- Find the ratio. Use the one the form or platform names. If it names none, 1:1 suits square posts, 4:5 suits portrait posts and 9:16 suits vertical video. Recommendations change, so check the preview in the app.
- Crop. Open the crop tool, choose the shape and drag the frame over the subject, keeping some headroom above the head. For exact positions, type X, Y, Width and Height in pixels. The shapes offered are 1:1, 4:5, 3:4, 16:9, 9:16, a circle and Free, so type pixels for any other ratio.
- Pad instead if the subject touches an edge. The square tool keeps the whole photo.
- Set the final size. After cropping, use the resize tool. Its Portrait preset is 1080 × 1350, which is 4:5, and its HD preset is 1920 × 1080. Crop to fill cuts to shape in one step, and Fit with padding adds a border.
Edge cases
- Circles. The crop tool saves a circle as a transparent PNG, because the corners must be transparent. The profile picture guide covers that case.
- Landscape to portrait. A landscape photo can become a tall frame only by keeping a narrow strip. That is why such crops often lose the subject, and padding is the better choice.
- Approximate names. The resize tool's Link preview preset, 1200 × 630, is about 1.9 to 1, not 16:9. Check the pixel numbers, not the name of the shape.
- Rotation. Rotate 90° in the crop tool turns the photo before you choose the frame, which changes which parts are kept.
- Crop from the original. Each save of a JPG adds a little loss. Crop the full-size original, resize at the end, and avoid cropping a copy that was already compressed.
