Body Fat Calculator

Male (U.S.): BFP = 86.010 x log10(waist - neck) - 70.041 x log10(height) + 36.76

Female (U.S.): BFP = 163.205 x log10(waist + hip - neck) - 97.684 x log10(height) - 78.387

Male (Metric): BFP = 495 / (1.0324 - 0.19077 x log10(waist - neck) + 0.15456 x log10(height)) - 450

Female (Metric): BFP = 495 / (1.29579 - 0.35004 x log10(waist + hip - neck) + 0.22100 x log10(height)) - 450

Adult male: BFP = 1.20 x BMI + 0.23 x Age - 16.2

Adult female: BFP = 1.20 x BMI + 0.23 x Age - 5.4

Body fat percentage is most useful when tracked over time. A single reading helps set your starting point, but weekly or bi-weekly re-checks are better for monitoring progress.

After calculating, use the "Use This in TDEE Calculator" action to estimate daily calorie needs with your body fat included. This can improve calorie target personalization compared with weight-only estimates.

The U.S. Navy method is a field estimate. It is practical and useful for consistency, but it can differ from lab-based methods.

Hydration, food intake, and measurement technique can all influence outputs. If results seem unrealistic, remeasure carefully and compare across multiple check-ins.

For most people, every 2-4 weeks is enough. Body composition changes gradually, and measuring too often can create noise without adding useful signal.

Pair your body fat trend with body weight, waist change, and performance in training. Looking at all three together gives a clearer picture than any one metric alone.

Is this exact? No. It is an estimate that is most useful for trend tracking.

What if my result looks too high or low? Re-check measurements and ensure your tape placement matches the guide above.

Can I use this for calorie planning? Yes. After calculating, continue to TDEE results and use the prefilled body-fat estimate for planning.

Body weight by itself does not tell you how much of your mass comes from fat, muscle, bone, or water. Two people can have the same body weight and very different body composition profiles. This is why body-fat percentage can be more actionable for goal setting than scale weight alone.

BMI is useful for population-level screening, but it cannot distinguish fat mass from lean mass. Active people who carry more muscle can appear overweight by BMI while maintaining a healthy body-fat range. Combining BMI with body-fat estimates and waist measurements generally gives better context.

A practical approach is to track three indicators together: body-fat percentage trend, body weight trend, and waist circumference trend. When these signals align over multiple weeks, decision-making around calories and training becomes more reliable.

After estimating body fat, move into your TDEE result and pick a calorie target that matches your goal. For most people cutting body fat, a moderate deficit is easier to sustain than an aggressive one. A slower approach often preserves more lean mass and supports better training quality.

Prioritize protein intake, resistance training, sleep quality, and consistent step count. These fundamentals usually matter more than short-term protocol changes. Reassess every 2-4 weeks and adjust calories based on trend data rather than day-to-day fluctuations.

If progress stalls, reduce calories slightly or increase daily activity before making large changes. Small, controlled adjustments are easier to evaluate and less likely to reduce adherence.

For muscle gain, body-fat percentage helps you choose when to lean bulk versus maintain. If body fat is already elevated, spending time at maintenance or a small deficit may improve long-term outcomes before entering a surplus.

When bulking, use a modest calorie surplus and monitor rate of gain. Rapid weight gain often increases fat faster than muscle. A slower, controlled surplus with progressive overload usually produces cleaner progress.

Use recurring check-ins to decide whether to continue the surplus, pause at maintenance, or run a short cut. This cycle-based approach helps balance performance with body composition.

If you have a history of metabolic disease, recent major weight changes, disordered eating patterns, or are currently pregnant/postpartum, personalized support from a qualified professional is recommended.

Clinical methods and practitioner oversight can provide more precise interpretation and safer planning than generalized formulas alone.