The definition
reachable viewers = total viewers × (1 − top-10 viewer share)
- Total viewers is the average number of people watching the category across an edition's sampling runs.
- Top-10 viewer share is the fraction of those viewers watching the category's ten largest live channels, averaged the same way.
A category's viewer count tells you an audience exists. Its concentration tells you how much of that audience the biggest channels already hold. Neither answers the question a small streamer is asking: how many viewers are watching somewhere other than the top of the directory. Reachable viewers puts both numbers into one.
Why it needs both numbers
Either input read alone points the wrong way. Two categories from the September 2026 edition show how.
Concentrated, with viewers left over
In The Last of Us Part II Remastered, the ten largest channels held 96% of viewers. Read on concentration alone, that looks shut. But 7,703 people were watching, so 277 of them were on other channels.
Evenly spread, with few viewers to share
Wobbly Life spread its audience evenly: its ten largest channels held 55%. That reads well until you count. 57 live channels were sharing 108 viewers, which leaves 49 reachable viewers across the whole category.
A rule that scores low concentration as good would rank the second category above the first. Reachable viewers measures both on the same scale.
From the September 2026 edition. The examples are recalculated for every edition.
How it is calculated
Reachable viewers is calculated for every category in every edition of the Twitch Category Saturation Report, from that edition's total viewers and top-10 viewer share. Both inputs are fixed when an edition is published, so a past edition's figure never changes.
The inputs come from the report's own sampling: four readings a day from Twitch's public API. The latest edition explains how the data is collected.
A category with no concentration reading has no reachable viewers figure. The CSV leaves that cell empty, and an empty cell never means zero. Worked examples and edition totals use ranked categories only.
Reachable viewers joined the dataset on 24 October 2026. Editions published before then gained it as a new final column in their CSV, and no other figure in those files changed.
What it does not tell you
Reachable viewers counts people watching outside the ten largest channels. It does not say whether any of them would watch a new channel, and we make no claim that a category with more reachable viewers grows a channel faster than one with fewer. It describes how an audience is spread across a category, and what happens in that category depends on everything this data cannot see.
Cite this metric
The definition and every figure are published under CC BY 4.0. Use the term, quote the numbers, and build on them, with credit to Streamer Growth Network. Cite this page for the definition, and the dated edition for any figure you quote.
How to cite the definition
Quoting a figure? Use the citation on the September 2026 edition, so the number and the page it came from always match.
Where to find the numbers
Every edition of the Twitch Category Saturation Report includes reachable viewers for each ranked category in its CSV. Past editions are in the archive. To see one category's numbers in detail, open its page from the edition's rankings table, or try where an average viewer count sits against the same sampled data.