Every founder asks this eventually, usually about ten minutes after their first post that did unexpectedly well or unexpectedly badly. The answer people want is a number. The honest answer is that the number on its own tells you almost nothing.
Why a single number cannot exist
Reach on LinkedIn scales with the audience the platform has to show a post to, and that audience is mostly your followers plus the people who engage with them. So the same post, word for word, is a triumph on one account and a disappointment on another.
Two thousand impressions is a strong week for someone with 900 followers and a bad day for someone with 40,000. Any article that quotes you a target without first asking how many followers you have is filling space.
That is why the question is worth rephrasing. Not "is this a good number" but "is this a good number for me", which has two answers you can actually compute.
The first comparison: against your own followers
Divide the post's reach by your follower count.
A post that reaches a small fraction of your own audience is telling you something about that post. A post that reaches well past your follower count has been carried beyond your network by people engaging with it, which is the only way reach grows.
Watch this ratio over ten or twenty posts and you get something a single figure never gives you: the shape of your own distribution, and which posts break out of it.
One caution. Follower count is not the same as the audience LinkedIn actually shows you to. Dormant followers, people who followed for a job post two years ago, and connections who never open the app all count in the number and none of them count in the feed. So read the ratio as a rough denominator, not a precise one.
The second comparison: against your own history
This is the one that matters, and it is the only benchmark you can genuinely see.
Take your last ten or twenty posts, work out your median reach, and read each new post against it. Median, not average, because one breakout post drags an average up and makes every normal post look like a failure afterwards.
Now you have sentences that are actually useful. This post did twice my median. This one did half. That is a fact you can write the next post from, in a way that "4,000 impressions" never is.
Inside Sonar this is the number we show rather than raw reach, because "earns about twice your average" is an instruction and a raw count is trivia.
Three things that distort the reading
Judge after two days, not two hours. Most of a post's reach arrives in the first 48 hours. An early read is mostly a read of who happened to be online when you published.
A tiny sample is noise. Below a few hundred people reached, the ratios bounce around for reasons that have nothing to do with the writing.
Impressions and members reached are different numbers. Impressions count screens, members reached counts people, and dividing one by the other tells you whether anyone came back to the post. That distinction is worth understanding properly, and it is in what members reached means.
What to do when the number is bad
Resist the urge to change the format. A post that underperformed your median usually underperformed on substance: it said something a reader could have got anywhere, or it said something true but with no decision attached.
The fix is almost never a better hook on the same thin material. It is different material. A post about a decision you actually made will outperform a well-hooked post about a general principle, most weeks, on most accounts.
If you find that the specific material is the hard part, the problem is usually retrieval rather than ideas, which is a different problem with a different fix.
Questions
Does LinkedIn show me my own median anywhere?
No. The analytics panel shows each post's numbers individually and a rolling total, but it will not compute a median across your posts or tell you where a new post sits against it. You have to do that yourself, in a spreadsheet, or use something that holds your history for you.
Can a tool pull my impressions automatically?
Not through LinkedIn's API, which does not return a member's own post analytics to any third party. Anything showing you impressions has either had you paste them in, or is reading them from the page in your own browser, or is showing you public engagement counts and calling them reach. Sonar takes the second route, with an extension that reads only what LinkedIn has already labelled on your own analytics pages.
Should I compare myself to other founders' numbers?
Only for reach relative to followers, and even then loosely. Absolute impressions across accounts compare nothing, because the follower bases differ. Engagement per thousand people reached is the fairer cross-account figure, and it is the one we use when comparing an account to the people it competes with for attention.