OG Image Aspect Ratio: Why 1.91:1 Dominates
The Open Graph image aspect ratio is 1.91:1 — a 1200×630 pixel card. That single ratio renders correctly on Facebook, LinkedIn, Discord, and as an X (Twitter) summary_large_image card, which is why nearly every blog and CMS exports to it. This post explains where 1.91:1 came from, why it beat more familiar ratios like 16:9, and the two places it quietly breaks.
What aspect ratio is an OG image?
A 1.91:1 ratio means the image is 1.91 times wider than it is tall. The canonical dimensions are 1200×630 pixels (1200 ÷ 630 = 1.905, which rounds to 1.91:1). This is the size the Open Graph protocol's og:image tag is expected to point to, and the size platforms reserve space for when they build a preview card.
It is not 16:9. A 16:9 image (like 1200×675) is taller; a square is 1:1. The Open Graph ratio sits between a widescreen video frame and a banner — wide enough to feel cinematic, short enough to not dominate a feed.
Why did 1.91:1 become the standard?
The short answer: Facebook picked it, and the web followed. Facebook's sharing documentation recommends 1200×630 for a large preview, and because Open Graph tags are read by every other major platform, that recommendation propagated. LinkedIn, Discord, and X all read the same og:image tag, so matching Facebook's ratio meant matching everyone at once.
og:image tag — the dimensions that fixed 1.91:1 as the de facto Open Graph ratio. — Facebook Sharing docs, 2026The deeper reason 1.91:1 works is that it's a strong feed shape: wide enough to read as a banner, short enough not to dominate the feed. And because every major platform reads the same tag, one correctly-ratioed asset renders almost everywhere.
summary thumbnail. — X (Twitter) Cards docs, 2026How do the platform ratios actually compare?
Every "1.91:1" platform is within a pixel or two of 1200×630. The differences are rounding, not real divergence — except Slack and iMessage, which use genuinely different shapes.
| Platform | Recommended size | Aspect ratio | Notes |
|---|---|---|---|
| 1200×630 | 1.91:1 | The reference spec | |
| X / Twitter (large) | 1200×628 | 1.91:1 | summary_large_image card |
| 1200×627 | 1.91:1 | Clips a few edge pixels | |
| Discord | 1200×630 | 1.91:1 | Reads og:image directly |
| Slack (expanded) | 1200×600 | 2:1 | Slightly wider than 1.91:1 |
| iMessage | 1200×1200 | 1:1 | Square; favors a short title |
For the full per-platform pixel reference — including minimum sizes and file-size ceilings — see the 2026 social media image size cheat sheet.
Where does 1.91:1 break?
Two places, both predictable.
Cropping at the edges. Different apps trim the same 1.91:1 image differently — Facebook shaves the sides on mobile, LinkedIn clips a few edge pixels. The fix is a safe zone: keep your logo, headline, and any text inside the center, leaving roughly a 60-pixel margin on all sides (about a 1080×510 region on a 1200×630 card). Anything outside that band should be decorative only.
Non-1.91:1 channels. Slack's expanded unfurl is 2:1 and iMessage prefers a 1:1 square. A 1.91:1 card still appears in both, but it won't fill the frame the way a native-ratio image would. For most blogs this is an acceptable trade — you ship one 1.91:1 asset and accept slightly imperfect rendering in two high-trust DM channels.
The ratio is only half the battle; the tags have to be right too. The og:image value must be an absolute HTTPS URL — a relative path is the single most common reason a correctly-sized card still renders blank. Walk the full tag set in the Open Graph meta tags reference, and if a preview won't appear at all, work through why your link preview is broken.
The one-line takeaway
Export every social card at 1200×630 (1.91:1), keep your content inside the center safe zone, and serve it from an absolute HTTPS URL — that covers every platform that reads Open Graph tags. Generating a correctly-ratioed, branded 1.91:1 card for every post automatically is exactly what Social Card Studio does.
Frequently asked questions
What is the correct aspect ratio for an OG image?
1.91:1 — a 1200×630 pixel image. Facebook, LinkedIn, Discord, and X (as a summary_large_image card) all read this ratio, so a single 1.91:1 asset covers nearly every platform that builds a link preview.
Why is the OG image ratio 1.91:1 and not 16:9?
1.91:1 (≈1.905) is slightly wider and shorter than 16:9 (1.778). Facebook set 1200×630 as its recommendation years ago and the rest of the web standardized on those tags, so 1.91:1 became the de facto Open Graph ratio even though it isn't a familiar video ratio.
What happens if my OG image is the wrong aspect ratio?
Platforms either crop it to fit their frame — cutting off your logo or headline — or fall back to a small square thumbnail. A 16:9 or square image won't error, but it will be trimmed unpredictably across apps, which is why 1.91:1 is the safe choice.
Does the OG image ratio need to be exactly 1.91:1?
Close is fine. LinkedIn uses 1200×627 and X uses 1200×628 — all round to 1.91:1. Stay within a few pixels of 1200×630 and keep critical content in the center safe zone, and every platform renders it correctly.