Why the crop table matters more than the ratio
Knowing your image is 16:9 is not useful on its own. What you need to know is what happens when you put it somewhere that expects 9:16, and the answer is that nearly half of it disappears.
Every platform fills its frame and crops the overflow. The table shows which axis is cut and by how much, so you can re-crop deliberately or design at the right ratio in the first place.
The ratios worth knowing
4:5 is the Instagram feed maximum, the tallest a feed post can be without cropping, and therefore the most screen space. 9:16 covers stories, reels, TikTok and Shorts. 1:1 is the safest cross-platform ratio because everything crops from square without losing much.
Designing at 4:5 and 9:16 covers most of a content calendar. A 1:1 export from a 4:5 master loses the top and bottom evenly, which is usually survivable if the subject is centred.
Frequently asked questions
What aspect ratio should I use for Instagram?
4:5 portrait, which is 1080 x 1350 pixels. It is the tallest the feed accepts without cropping, so it takes the most vertical space as someone scrolls. Square at 1:1 also works and is easier to reuse elsewhere.
How do I convert 16:9 to 9:16 without ruining it?
You cannot do it without losing about 44% of the width, or adding padding. For video, most editors let you reframe so the crop follows the subject. For stills, re-crop deliberately rather than letting the platform pick the centre.
What does the decimal ratio mean?
Width divided by height. 1.7778 is 16:9, 0.8 is 4:5, 0.5625 is 9:16. It is useful when a tool asks for a ratio as a single number rather than two.
Does resizing change the aspect ratio?
Not if you scale both dimensions by the same factor, which is what this calculator does. Changing one dimension alone stretches the image, which is the most common way an asset ends up looking subtly wrong.