Guide

Aspect ratios and sizes

A ratio is only a promise about the shape. What it costs depends on the photo you start from — and when you reach it by adding canvas instead of cutting, the cost is measured in pixels you have to build.

Reading a ratio

An aspect ratio is width divided by height, written as two small whole numbers. 16:9 means sixteen units across for every nine down, whatever the units are; 1920 x 1080 and 3840 x 2160 are both 16:9. Two photographs of the same ratio can be any size, and two of the same size can only be one ratio.

Getting from one ratio to another means changing one side relative to the other, and there are only two ways to do that: remove some of the long side, which is a crop, or add to the short side, which is what this site does. The table below is the second way, worked out for every shape worth a row.

The short side grows. The long side is never touched. Every figure below follows from that one rule.

Every common ratio, and what it costs two real photos

Canvas needed to reach each ratio without cropping, and the share of it that is built
Ratio	From a 4000 x 3000 camera photo	From a 1080 x 1920 phone still	Open
16:9Widescreen video, slides, most monitors and TVs	5,333 x 3,00025% built, model offered	3,413 x 1,92068% built	16:9 in the tool
9:16Stories, reels, Shorts and phone wallpapers	4,000 x 7,11158% built	already this shape	9:16 in the tool
1:1Square feed posts, profile pictures, marketplace listings	4,000 x 4,00025% built, model offered	1,920 x 1,92044% built, model offered	1:1 in the tool
4:5The tallest portrait a feed shows without trimming	4,000 x 5,00040% built, model offered	1,536 x 1,92030% built, model offered	4:5 in the tool
3:235 mm film and most interchangeable-lens cameras; 6 x 4 prints	4,500 x 3,00011% built, model offered	2,880 x 1,92063% built	3:2 in the tool
2:3The same frame on its side: portrait prints and pins	4,000 x 6,00050% built, model offered	1,280 x 1,92016% built, model offered	2:3 in the tool
4:3Phone and compact cameras in their native mode; older screens	already this shape	2,560 x 1,92058% built	4:3 in the tool
21:9Ultrawide monitors and cinematic banners	7,000 x 3,00043% built, model offered	4,480 x 1,92076% built	21:9 in the tool
3:1Profile headers and letterbox banners	9,000 x 3,00056% built	5,760 x 1,92081% built	3:1 in the tool

Anything past 2.5 times the area of the original is marked: at that point most of what you save was built, and the tool says so above the Save button. It still works, and on a plain sky or a studio wall it can look entirely natural; on a room full of people it will not.

Exact sizes, when the platform names pixels

Some slots are specified as a pixel size rather than a shape. For those the tool has an Exact size mode: the photo is fitted inside the size you name — scaled down if it is bigger, never enlarged unless you allow it — and the rest of the frame is built at that size. The links open it already set.

Platform sizes the tool opens at directly
Slot	Pixels	Open
Portrait postInstagram feed, 4:5	1,080 x 1,350	Open at this size
Square postInstagram and Facebook feed	1,080 x 1,080	Open at this size
Story or reelInstagram, TikTok, Shorts, 9:16	1,080 x 1,920	Open at this size
Video frameYouTube thumbnail, 16:9	1,280 x 720	Open at this size
Full HDSlides and screens, 16:9	1,920 x 1,080	Open at this size
Link previewOpen Graph card, 1.91:1	1,200 x 630	Open at this size
X headerProfile banner, 3:1	1,500 x 500	Open at this size
LinkedIn bannerProfile background, 4:1	1,584 x 396	Open at this size
PinPinterest, 2:3	1,000 x 1,500	Open at this size

Platforms revise these numbers every year or two, so check the slot you are filling. The tool takes any width and height, and the Export panel can write several of these sizes from one photo into a single ZIP.

Choosing between ratio and size

Use a ratio when the file will be shown at more than one size, or when you want every pixel of the original kept at its own resolution — a print, an archive, a slide that will be projected. Use an exact size when a platform will resize whatever you give it anyway: fitting the photo yourself means you, not their encoder, decide how the edge is built.

The awkward questions

Why does the table say a 16:9 version of a phone still is 3,413 pixels wide?

Because the tool reaches a shape by growing the short side and never by trimming the long one. A 1080 x 1920 frame is 1,920 pixels tall; the widest 16:9 canvas that keeps all of it is 1,920 x 16 / 9 = 3,413 pixels wide. The 1,080 columns you photographed sit in the middle and 2,333 are built around them.

What does "model offered" mean in the table?

The edge model is only offered while the canvas is at most 2 times the area of the photograph, because past that more of the file is generated than photographed. It has a second limit on the depth of the deepest new edge, which the tool checks against your actual photo; the table checks only the area, so treat it as the most optimistic answer.

Is an exact platform size the same as its ratio?

Not quite. 1080 x 1350 is 4:5, but a 4000 x 3000 photo taken to 4:5 by growing comes out 4000 x 5000, which the platform then shrinks. Choosing the exact size instead fits the photo inside 1080 x 1350 and builds the rest at that size, so the file you save is the file they show. It is the only mode in which the photograph itself is resized, and the tool prints the figure.