Use a body fat scale or smart scale and follow the device instructions
Measure with skinfold calipers at standard body sites and use a body fat formula
Use a tape measure method such as the U.S. Navy formula
Get a DEXA scan for the most accurate estimate
Use hydrostatic weighing if available
Use bioelectrical impedance analysis through a gym, clinic, or home device
Calculate with the U.S. Navy method using height, neck, waist, and hips for women
Compare your measurements to a body fat calculator online
Track the same method consistently over time for the best trend data