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How LinkedIn and X actually work

Short, sourced guides for founders and experts who post on both networks. Every number links to where it came from, and we say so when the platforms do not publish one.

Updated 30 Sept 2026

Timing

When to post, and how to schedule it.

The best time to post on LinkedIn, from the dataWhat Buffer and Sprout Social found, by day, shifted into your time zone.The best time to post on X, from the dataBuffer says mornings, Sprout says afternoons. Both, by day, in your time zone.How to schedule LinkedIn posts, and where to find themNative steps, where scheduled posts live, and the limits.

Algorithms

How each feed ranks posts, from the source.

How the LinkedIn algorithm works, from what LinkedIn has saidWhat LinkedIn has said about its feed, dated, with the myths marked.How the X algorithm works, read from the codeThe current ranking weights from X's own repository, and what they mean.

Limits and formats

Character limits, image sizes and document posts.

LinkedIn character limits, all in one placePosts, headline, About, notes, InMail and ads in one sourced table.The X character limit, and how X really counts280, weighted: why emoji count as 2 and every link as 23.LinkedIn post image sizes, from LinkedIn's own pagesPost shapes, cover photos, Page images and file limits, with sources.How to post a carousel on LinkedInUpload a PDF as a swipeable post: steps, specs and slide tips.

Writing

Hooks, hashtags, personal branding and getting help.

Hook writing for LinkedIn and X postsWhy the first line decides the read, and nine formulas that work.Do hashtags work on LinkedIn?What LinkedIn changed, what studies show, and a simple rule.LinkedIn personal branding for founders and expertsWhat buyers want, profile basics, and a 30 day plan.LinkedIn ghostwriting: the rules, the options, the voiceWhat LinkedIn's rules say, and a ghostwriter vs a tool vs yourself.

Questions

Where do the numbers on these pages come from?

From the platforms' own help pages, developer docs and open source code, and from published studies such as Buffer's and Sprout Social's. Each page lists its sources with the date we checked them.

How often are these guides updated?

Each page shows the date its facts were last checked. Platforms change often, so we recheck the limits and the algorithm pages first.

What if a source disagrees with another?

We say so on the page and show both. For example, the two biggest best time studies point to different hours, and LinkedIn's own image pages differ by a pixel.