How do I calculate BF accurately for myself?

Sorry if it's a duplicate but I'm finding trouble calculating BF. In my bodyspace account it automatically set BF to 4% based on height and weight. I raised it to 7% because I don't think I have very low bodyfat. So what's an accurate method to calculate my BF?
Thank you so much!

by Angileena via Bodybuilding.com Forums - Female Bodybuilding