In more detail
Organic reach counts the people the algorithm shows your post to for free, based on signals like follower relationships, past engagement, and topic relevance. It sits opposite paid reach, which you buy through ads. Most platforms have squeezed organic reach over the years, so only a fraction of your followers see any given post, often well under 10 percent on Facebook. It matters because it shows how far your content travels on its own merit, which is a cleaner read on content quality than numbers you paid to inflate.
Example
If you have 5,000 followers and post without any ad budget, and 600 unique people see it through their feeds, the Explore page, or shares, your organic reach for that post is 600. The other 4,400 followers never had it surface in their feed.
RedaQuest analytics breaks your reach into organic and paid so you can see how far your content travels on its own before you spend a cent.
FAQ