2.39:1 aspect ratio
2.39:1 is the modern anamorphic cinema frame, the widest ratio in general delivery use. It is often written 2.40:1 and was 2.35:1 before the standard was revised.
At a glance
- Ratio
- 2.39:1
- Decimal value
- 2.39 (width divided by height)
- CSS aspect-ratio
- aspect-ratio: 2.39 / 1;
- Common pixel dimensions
- 2048 x 858, 4096 x 1716, and 1920 x 804 for a home master
- Suits
- Cinematic video, landscape stills and title sequences
- Struggles with
- Screens of any kind, since nothing is shaped like this
In detail
The ratio is a survivor of a photochemical trick. Anamorphic lenses squeezed a wide image onto a standard film frame horizontally and a matching projector lens unsqueezed it, which let studios deliver a very wide picture without changing the film stock. The resulting projected shape settled at about 2.35:1, and a revision to the standard in the early 1970s moved it to 2.39:1.
Both numbers are still in circulation, and 2.40:1 is used as a rounded shorthand for the same frame. The difference between 2.35 and 2.39 is under two percent, invisible in practice, and it is only worth caring about when matching archival material where a hard cut between two slightly different frames shows as a jump at the top and bottom edges.
No display is this shape, which is the point rather than a problem. A film shown on a 16:9 television is letterboxed with visible bars, and that letterboxing is now a deliberate signal: framing a video at 2.39 tells a viewer it is meant to be cinematic before a single frame plays.
It is close enough to the 43:18 of a 3440 by 1440 ultrawide panel, at 2.3889, that content at this ratio very nearly fills such a screen. That near coincidence is the main reason ultrawide monitors are marketed to people who watch films.
Examples
frame: 1920 x 1080
picture: 1920 x 804 // 1920 / 2.39 = 803.3, rounded to an even number
bars: 138 pixels top and bottom2.39 : 1 the cinema frame
43 : 18 = 2.3889 a 3440 x 1440 panel
// a difference of about 0.05 percentThings that catch people out
- 2.35, 2.39 and 2.40 all name effectively the same frame. Mixing them in one edit shows as a jump at the horizontal bars.
- Bars added in the export are baked into the picture and cannot be removed by a player. Deliver the picture at its own ratio when the platform supports it.
- Cropping 16:9 footage to this ratio loses a quarter of the height, so it has to be planned when shooting, not applied afterwards to rescue a composition.
Try it: Aspect Ratio Calculator
Enter a width and a height, or a ratio and one dimension, and it solves the missing one, simplifies the ratio, counts the megapixels and gives you a copyable CSS value.
Aspect Ratio Calculator
LOCAL · Browser-OnlyCalculate and convert aspect ratios for images, videos, and screens
1920 x 1080px · 16:9 · 1.7778:1
Common Aspect Ratios Reference
| Ratio | Decimal | Common Use |
|---|---|---|
| 16:9 | 1.778 | Widescreen TV, YouTube, monitors |
| 4:3 | 1.333 | Classic TV, iPad, presentations |
| 1:1 | 1.000 | Instagram square, profile pictures |
| 21:9 | 2.333 | Ultrawide monitors, cinema |
| 9:16 | 0.563 | Phone vertical, TikTok, Reels |
| 3:2 | 1.500 | 35mm photography, MacBook |
| 2:3 | 0.667 | Portrait photography, posters |
| 5:4 | 1.250 | Large format photography, older monitors |
| 32:9 | 3.556 | Super ultrawide monitors |
| 2.39:1 | 2.390 | Anamorphic cinema, widescreen films |
Related Image and canvas sizes
All image and canvas sizes →21:9 aspect ratio
The 21:9 marketing label at 2.3333, the 43:18 and 64:27 shapes that real ultrawide panels actually use, and how to design for the gap between them.
Ultrawide screen size: 3440 by 1440
The 3440 by 1440 ultrawide panel, why its true ratio is 43:18 rather than the advertised 21:9, and how it relates to a QHD display.
Letterboxing versus cropping
What happens when an image does not match its frame: bars that keep everything, or a crop that discards the edges. How object-fit chooses between them.
What is an aspect ratio?
Aspect ratio is width divided by height, and it says nothing about resolution or file size. How to simplify one, read it as a decimal, and use it correctly.
The CSS aspect-ratio property
How the aspect-ratio property works, what happens when a width and a height are also set, and how it removes layout shift when media loads.
DPI versus pixel dimensions
Why a raster file only stores pixels, what the DPI number in its metadata does and does not change, and how to work out a print size from a pixel count.
Tools for this
- Aspect Ratio Calculator Free online aspect ratio calculator - calculate and convert aspect ratios for images, videos, and screens
- Image Cropper Free online image cropper - crop images with preset aspect ratios and free-form selection