Having an accurate understanding of your body composition is one of the most important things in:

• Setting up a nutrition plan that is the most effective
• Preserving/building the most muscle possible
• Keeping your hormone levels in check
• Knowing how much fat you have to lose, or how long you can bulk for
• It's just a good metric.

If you're looking for something that actually gives you a good answer, instead of methods based on bodies that aren't yours.

Grab this bodyfat calculator and start using it.