There are wide ranges but it's more about how you feel personally and what you've noticed over time. Some men have below average T but feel great and build serious muscle anyway.

The two sigma range is something like 300-900 with std being 150 and median 600. This is for what is labeled as healthy 18-39 men. It doesn't include obese men.

If you want to take something away from it, just get yourself measured a few times over a few years. Then later if you have issues that relate to low T or whatever you can flag it with your doctor. In my case, it was super important because I found out I am in the top 0.01% of (healthy) total T producers. If I had "low T" type symptoms and went to my doctor without that information - they'd be like, "no, your T is amazing actually."

Everyone has a different baseline. I only wish I started measuring before I was in my mid-30s because I feel my levels before were even more ridiculous.