Reach rate: how to calculate it and why it falls as the account grows

The maths is direct: reach rate = reach ÷ followers × 100. A post that reached 3,000 accounts on a profile with 10,000 followers has a 30% reach rate.

What it solves is the comparison problem. Absolute reach is a size metric: a big profile reaches more by definition, and that says nothing about the content. Dividing by the base turns it into efficiency, and then it makes sense to compare one week with another, one format with another, or your profile with a competitor of similar size.

One quirk confuses many people: the rate can exceed 100%. That happens when content reaches far more people than your base, meaning delivery to non followers was large. It is not a calculation error, it is a discovery signal.

This is expected behaviour, not a fault. Every base accumulates people who followed at some point and stopped using the app, or stopped caring about the subject. Those accounts stay in the denominator and never show up in the numerator.

Add the mechanics of the algorithm: feed delivery depends on the interaction history between the two accounts. The bigger the base, the higher the share of people with a weak history, and the smaller the slice that receives content in the first moment.

Practical consequence: comparing today's reach rate with the one from two years ago, when you had a third of the followers, almost always produces a wrongly pessimistic conclusion. The honest comparison is against accounts of similar size, or against your own recent trend.

There is no universal number, and any table promising one is reporting the average of a sample that is probably not yours. The rate varies with account size, niche, format and the share of discovery content.

The benchmark that works is your own. Calculate the rate for your last thirty pieces, separated by format, and use the median as your baseline. Median rather than mean, because a viral drags the average and makes everything else look like failure.

Two readings worth more than the absolute number:

• Trend. Is the rate stable, rising or falling month over month, as the base grows.
• Spread. If some posts sit far above the median, it is worth understanding what they share. That is where the topics that work live.

• Inflated base. Fake followers and giveaway followers sit in the denominator and never interact, dragging the rate down with nothing having got worse.
• Mixing formats. Reels reach far more non followers than a photo. Comparing them on the same line makes no sense.
• Using it instead of engagement. Reach rate measures distribution, not response. For response, the number is engagement rate.
• Ignoring measurement timing. Reels accumulate reach for weeks, so a rate measured at 24 hours understates.

• I use the follower count from the post date, not today's.
• I calculate separately by format.
• I use the median of the last thirty as a baseline, not the mean.
• I am not alarmed by a rate above 100%: that is delivery to non followers.
• I do not compare today's rate with the one from when the account was much smaller.