Multiply inches by 2.54 to get centimeters, and multiply pounds by 0.4536 to get kilograms. For example, a 34-inch waist is 86.4 cm, and 180 pounds is 81.6 kg. This calculator handles the conversion internally if you switch to metric units.

Yes, body fat percentage categories are universal regardless of the unit system used for measurements. The Navy formula produces the same percentage whether you input inches or centimeters — only the internal math differs.

Measure your waist at the navel level, your neck just below the Adam's apple, and your hips at the widest point (women only). Use a flexible tape measure, keep it level and snug without compressing skin, and measure to the nearest 0.5 cm.