Yes, you can see organic vs. paid reach separately for a boosted Facebook post, even without using Ads Manager.
1) Go to Your Facebook Page
Use the account that manages the page.
2) Find the Boosted Post on your timeline.
3) Click on “View Insights” (or “Boost Summary”) below the post.
4) Under Post Insights, you'll see:
- Total Reach
- Paid Reach
- Organic Reach
Facebook breaks these out clearly—often as bars or side-by-side numbers—so you can compare both.
Note:
This only works for posts boosted from the Page itself.
If you're using Meta Business Suite, you can go to “Content” > “Published posts” and click on the post to see the same breakdown.