Formats and safe framing
16:9, 9:16, 1:1, 4:5: the resolutions each platform expects, and the zones you should keep clear.
The ratios in use, and the sizes that go with them
Every number below is a real delivery size, not a rounding. Keep the shape, change the pixel count: 16:9 is 16:9 whether it is 1280 or 3840 wide.
| Ratio | Decimal | Usual sizes | Where it goes |
|---|---|---|---|
| 16:9 | 1.778 | 1920×1080 · 2560×1440 · 3840×2160 | YouTube, TV, almost every camera |
| 9:16 | 0.563 | 1080×1920 · 2160×3840 | Reels, Shorts, TikTok, stories |
| 4:5 | 0.800 | 1080×1350 | Instagram feed, portrait |
| 1:1 | 1.000 | 1080×1080 | Square feed post |
| 4:3 | 1.333 | 1440×1080 · 4096×3072 | Open-gate sensors, archive, older TV |
| 3:2 | 1.500 | 6000×4000 | Stills out of a 35 mm camera |
| 1.85:1 | 1.850 | 1998×1080 · 3996×2160 | Cinema, flat |
| 2:1 | 2.000 | 2048×1024 · 3840×1920 | Univisium, a lot of streaming drama |
| 2.39:1 | 2.390 | 2048×858 · 4096×1716 | Cinema, anamorphic scope |
What a reframe actually costs
Reframing is not resizing. Going to a narrower shape does not shrink the picture — it throws part of it away, and the part it throws away is the part you framed. These are the figures, from a 1920×1080 source:
| To | Largest crop | Kept | Cut from |
|---|---|---|---|
| 9:16 | 608×1080 | 32 % | the sides |
| 4:5 | 864×1080 | 45 % | the sides |
| 1:1 | 1080×1080 | 56 % | the sides |
| 4:3 | 1440×1080 | 75 % | the sides |
| 2.39:1 | 1920×803 | 74 % | top and bottom |
Two thirds of a frame is a lot to lose by accident. If a vertical cut is coming, the time to deal with it is on set: keep the action inside the center column, leave the edges to breathe, and the crop becomes a choice instead of a rescue.
How the ratio is worked out
ratio = width ÷ height, simplified by the greatest common divisor
1920 and 1080 share a divisor of 120, so 1920×1080 is 16:9. When the simplification lands on numbers nobody would recognize — 2048×858 gives 1024:429 — the useful form is the decimal one, and that is how cinema has always named its widest formats: 1.85:1, 2.39:1.
The crop figure comes from areas, not sides. The largest frame of the target ratio that fits inside the source is height × target ratio when the target is narrower, and width ÷ target ratio when it is wider. What you keep is that rectangle's area over the original's.
Frequently asked
What resolution is 16:9?
Any width and height that divide to 1.778. The ones in use are 1920×1080 (HD), 2560×1440 (QHD) and 3840×2160 (UHD, sold as 4K). All three are the same shape; only the pixel count changes.
What size should a vertical video be?
1080×1920 is the answer for every vertical platform — Reels, Shorts, TikTok and stories all take it. That is 9:16, the exact mirror of HD. Instagram also accepts 1080×1350, which is 4:5, and it is worth knowing: 4:5 fills nearly as much of a phone screen as 9:16 in the feed, while staying far closer to a normal frame.
How do you calculate an aspect ratio?
You simplify the two numbers like a fraction, by their greatest common divisor. 1920 and 1080 both divide by 120, which gives 16:9. Some sizes do not simplify into small numbers — 2048×858 would be 1024:429, which tells you nothing — so cinema states them as a decimal instead: 2.39:1.
How much of the picture do I lose going from 16:9 to 9:16?
68 %. You keep a 608×1080 column out of a 1920×1080 frame — a little under a third of the image. This is the single most useful number on this page, and it is why a vertical version is a decision you make before the shoot, not after.
What is 2.39:1, and why not 2.35:1?
It is the modern anamorphic scope ratio. 2.35:1 was the standard until 1970, when the projection aperture changed; everything since is 2.39:1, and the industry kept saying “2.35” out of habit. Both names point at the same widescreen shape.
Does cropping lose quality?
It loses pixels, which is not the same thing. Cropping a 3840×2160 frame to 9:16 leaves 1215×2160 — still more than a 1080×1920 delivery needs, so nothing visible is lost. Do the same crop on a 1920×1080 frame and you are left with 608×1080, which has to be scaled up to deliver. That is where it starts to show.