How to calculate body fat %

[tiredmama]

I opened my account yesterday, entered weight, but do not know how to calculate my % body fat. Can someone help me with this please.

[LorneR]

Fitbit DOES populate this value - and populates it with data which seems at least plausible - but I've no idea on what basis. I don´t have any fancy scales, and I don't enter it myself. So however does it calculate this? 

[Chezwick]

https://www.nhlbi.nih.gov/health/educational/lose_wt/BMI/bmicalc.htm

All information is in the link above.

[Workingongettin]

You mean the body fat % right? I have the inspire 3 and am getting a body fat % number from fitbit, but I don't have the scale. When I Google if the inspire 3 calculates it, I got a ai telling me it does, but I can't seem to drill deeper. It lead me here.