3:4 aspect ratio
3:4 is the tall portrait shape: 3 units wide for every 4 tall. 0 of the image sizes on this site use it.
Where 3:4 comes from
3:4 is the tallest single image the Instagram feed accepts, and it is also the shape of a profile grid tile. That combination makes it the one feed ratio the grid does not crop at all: what you post is what appears in your profile.
Which platforms use 3:4
No spec in the current dataset uses this exact shape.
3:4 in pixels
Every row below is calculated from the ratio rather than looked up, so the heights are exact where the arithmetic is exact and rounded to the nearest whole pixel where it is not. A fractional pixel is not something a file can store.
| Width | Height | Used by |
|---|
Cropping and letterboxing into 3:4
Taller than 4:5 by a small margin, which sounds trivial and is not, because the grid tile is 3:4. A 4:5 post loses a slice from each side in the grid; a 3:4 post loses nothing.
There are only two honest ways to put an image of one shape into a frame of another. Crop to fill keeps the frame full and throws away whatever does not fit, which is almost always what you want for a feed. Fit inside keeps the whole image and pads the remaining space, which is what you want when the image is a diagram, a screenshot or anything where losing an edge loses meaning. Scaling to fit without doing either, so the image is stretched, is the one option that is always wrong.
Work out a 3:4 size
Enter a width or a height and the calculator solves the other side. It runs in your browser and nothing is uploaded.
Other ratios
See the aspect ratio guide for the shapes side by side, or the full cheat sheet for every size on one page.