Body Fat Percentage Calculator
Estimate your body fat percentage with the US Navy tape method — plus lean body mass and your body fat category — using simple tape measurements.
General nutrition education only. Not medical advice.
Quick answer: how to use this result
This body fat percentage calculator uses the US Navy tape method: enter your height plus neck and waist measurements (and hips for women), and it estimates what share of your body weight is fat. Add your weight and it also estimates lean body mass. Treat the number as a starting point and re-measure every 2–4 weeks under the same conditions — the direction of change matters more than any single reading. If your goal is to lower the number, pair the result with the Calorie Deficit Calculator to set your daily calories.
What body fat percentage tells you
Body fat percentage is the fraction of your total body weight that is fat tissue. Two people can weigh exactly the same and look and perform completely differently because one carries more muscle and the other more fat. That is why a body fat estimate adds real information beyond the bathroom scale: it splits your weight into fat mass and lean mass, and progress in body composition means shifting that ratio — not just lowering the total.
Some body fat is essential. It insulates organs, stores energy and supports hormone production — roughly 2–5% in men and 10–13% in women is considered essential fat. Above that, ranges commonly used in fitness education run from "athlete" through "fitness" and "average" categories, which this calculator reports alongside your estimate.
How this body fat percentage calculator works
The tool implements the US Navy circumference method, developed by the Naval Health Research Center so body fat could be estimated with nothing more than a measuring tape. The formulas use the fact that fat distribution shows up predictably in a few circumferences:
The US Navy formulas (metric)
Men: 495 ÷ (1.0324 − 0.19077 × log₁₀(waist − neck) + 0.15456 × log₁₀(height)) − 450
Women: 495 ÷ (1.29579 − 0.35004 × log₁₀(waist + hip − neck) + 0.22100 × log₁₀(height)) − 450
All measurements are in centimetres. Because the method relies on tape placement, measuring the same spots the same way each time matters more than any single result.
How to take the measurements
Neck: just below the larynx (Adam's apple), tape sloping slightly downward at the front. Waist: for men, level with the navel; for women, at the narrowest point of the torso. Hips (women): around the widest point of the hips and buttocks. Keep the tape level and snug without squeezing, breathe out normally, and measure in the morning before eating for consistency.
Body fat categories at a glance
Widely used educational bands (based on ACE fitness categories) look like this. For men: essential fat 2–5%, athletes 6–13%, fitness 14–17%, average 18–24%, above average 25%+. For women: essential fat 10–13%, athletes 14–20%, fitness 21–24%, average 25–31%, above average 32%+. These are context bands rather than diagnoses — age, genetics and sport all shift what is normal and healthy for an individual.
BMI vs body fat: why they disagree
BMI divides weight by height squared and knows nothing about what the weight is made of. A rugby player and a sedentary office worker can share a BMI of 27 while one is at 12% body fat and the other at 28%. BMI remains useful as a fast, population-level screen — you can check yours with the BMI Calculator — but body fat percentage answers the more personal question of composition. Using both together gives a fuller picture than either alone: BMI for where your weight sits relative to height, body fat for what that weight consists of.
Lean body mass: the number worth protecting
When you enter your weight, the calculator also reports lean body mass — everything that is not fat, including muscle, bone, organs and water. Lean mass drives most of your resting calorie burn, so preserving it during weight loss keeps your metabolism higher and your strength intact. The two best-supported tools for protecting it are adequate protein (use the Protein Calculator for a personal gram target) and resistance training a few times per week. Some coaches set protein relative to lean mass rather than total weight, which is especially useful at higher body fat levels.
A worked example
Ahmed is 175 cm tall with a 38 cm neck and 92 cm waist. The men's formula gives him a body fat estimate of about 22% — the "average" band. At 82 kg, that is roughly 18 kg of fat mass and 64 kg of lean body mass. He sets a modest 500-calorie deficit with the Calorie Deficit Calculator (his maintenance from the TDEE Calculator is about 2,700 kcal), keeps protein near 130 g per day, and plans meals with the Meal Planner. Re-measuring monthly, a falling waist measurement with stable strength tells him the weight he is losing is mostly fat.
Accuracy and limitations
Tape-based estimates typically fall within 3–4 percentage points of laboratory methods such as DEXA scans — good enough for tracking, not for medical decisions. Results are least reliable at very high or very low body fat levels and for people with unusual fat distribution. Hydration, recent meals and tape tension all nudge the number, which is why consistent measuring conditions beat precision-chasing. If you need a clinical measurement, a DEXA scan or professional assessment is the appropriate route.
Turning your body fat estimate into a plan
A body fat number is only useful if it changes what you do. If your estimate sits above the range you want, the reliable sequence is: establish maintenance calories, set a moderate deficit, hold protein high, train against resistance, and re-measure every few weeks. Food choices carry the plan day to day — the Food Compare tool, the Food Comparisons library and the Food Calories Database help you find higher-protein, lower-calorie versions of meals you already eat.
FAQs: body fat percentage calculator
What is a healthy body fat percentage?
Commonly cited educational ranges are roughly 14-24% for men and 21-31% for women, with athletes often lower and essential fat around 2-5% for men and 10-13% for women. Healthy values vary by age, genetics and sport, so treat these ranges as context rather than pass/fail lines.
How accurate is the US Navy body fat calculator?
The US Navy tape method typically lands within about 3-4 percentage points of lab methods like DEXA for most people. Its real strength is consistency: if you measure the same way each time, the trend in your body fat estimate over weeks is meaningful even if the absolute number is slightly off.
How do I measure my waist, neck and hips correctly?
Use a flexible tape, keep it level and snug but not compressing the skin. Measure the neck just below the larynx, the waist at the navel for men or the narrowest point for women, and the hips at the widest point. Measure in the morning before eating, and take each measurement twice.
What is the difference between BMI and body fat percentage?
BMI only compares weight to height, so it cannot tell muscle from fat - a muscular person can have a high BMI and low body fat. Body fat percentage estimates the actual fat fraction of your weight, which makes it a better indicator of body composition, while BMI remains a quick population-level screening number.
How can I lower my body fat percentage?
Combine a moderate calorie deficit with adequate protein and resistance training. The deficit reduces fat mass while protein and training help preserve lean mass, so a larger share of the weight you lose is fat. Losing about 0.25-0.5 kg per week is a common, sustainable pace for improving body composition.
What is lean body mass and why does it matter?
Lean body mass is everything that is not fat - muscle, bone, organs and water. It drives most of your resting calorie burn and your strength, so preserving it during weight loss matters. This calculator estimates lean body mass when you enter your weight, and protein targets are often set relative to it.
Related tools and pages
General nutrition education only. Not medical advice. Tape-based body fat estimates are approximate; consult a qualified professional for clinical assessment.