How to Calculate Body Fat Percentage

Q: What is a healthy body fat percentage?

For men, 10–20% is generally considered fit to healthy. For women, 18–28% is the typical healthy range. Athletes may have lower values.

Q: How often should I measure body fat?

Measuring once every 4–8 weeks is sufficient for tracking progress. Daily measurements are not recommended as normal fluid fluctuations create noise in the data.

Understand the methods, healthy ranges for men and women, and what your number actually means for your health.

Body fat percentage is the proportion of your total body weight that comes from fat tissue. Unlike weight alone, it tells you how much of your body is metabolically active muscle, bone, and organ tissue versus stored fat. Knowing how to calculate body fat percentage gives you a clearer picture of your health and fitness progress than the scale alone.

Why body fat percentage matters more than weight

Two people can weigh exactly the same but have very different health profiles. A person with 15% body fat and another with 30% body fat at the same body weight will have completely different health risks, metabolic rates, and fitness capacities. Body fat percentage helps you track fat loss versus muscle gain — something weight alone cannot do.

Method 1 – The US Navy body fat formula

The Navy method uses circumference measurements and is one of the most accessible ways to estimate body fat at home. You need a measuring tape and the following measurements in centimetres.

For men: Measure neck circumference and waist circumference (at the navel). Height in cm.

Body Fat % = 86.010 × log10(waist – neck) – 70.041 × log10(height) + 36.76

For women: Measure neck, waist (narrowest point), and hip circumference. Height in cm.

Body Fat % = 163.205 × log10(waist + hip – neck) – 97.684 × log10(height) – 78.387

The Navy method typically has an accuracy of ±3–4 percentage points when measurements are taken correctly.

Method 2 – BMI-based body fat estimate

If you already know your BMI, you can estimate body fat using the Deurenberg formula:

Body Fat % = (1.20 × BMI) + (0.23 × age) – (10.8 × sex) – 5.4

Where sex = 1 for male, 0 for female. This method is less accurate than Navy measurements but useful for a quick estimate without measuring tapes.

Method 3 – Skinfold calipers

Skinfold calipers measure the thickness of subcutaneous fat at specific sites (chest, abdomen, thigh for men; tricep, suprailiac, thigh for women). These measurements are entered into validated equations such as the Jackson-Pollock formula to estimate total body fat. Accuracy is ±3–5% but depends heavily on correct technique and consistent measurement sites.

Healthy body fat percentage ranges

The American Council on Exercise (ACE) classifies body fat into the following categories:

Men – Essential fat: 2–5% | Athletes: 6–13% | Fitness: 14–17% | Acceptable: 18–24% | Obese: 25%+
Women – Essential fat: 10–13% | Athletes: 14–20% | Fitness: 21–24% | Acceptable: 25–31% | Obese: 32%+

Women naturally carry more essential fat due to hormonal and reproductive functions. Comparing a woman's body fat percentage to a man's chart leads to incorrect conclusions.

What affects body fat percentage

Age: Fat mass tends to increase and muscle mass decreases with age, even if weight stays constant
Diet: Calorie surplus consistently over time leads to fat accumulation
Resistance training: Building muscle increases lean mass and improves the fat-to-muscle ratio
Hormones: Thyroid function, cortisol, and sex hormones all significantly influence fat distribution
Sleep: Poor sleep increases cortisol and promotes fat storage, especially visceral fat

Visceral fat vs subcutaneous fat

Not all body fat carries the same health risk. Subcutaneous fat sits just beneath the skin and is relatively inert. Visceral fat surrounds internal organs and is strongly linked to cardiovascular disease, type 2 diabetes, and metabolic syndrome. A person can have a normal total body fat percentage but carry dangerous levels of visceral fat — which is why waist circumference is an important additional metric.

Frequently asked questions about body fat percentage

What is a healthy body fat percentage? For men, 14–24% is generally considered acceptable. For women, 21–31% covers the acceptable range. Athletes typically aim for lower ranges appropriate to their sport.

Is body fat percentage more accurate than BMI? Body fat percentage is generally more informative than BMI because BMI cannot distinguish between fat mass and muscle mass. A muscular person can have a high BMI but a healthy body fat percentage.

How often should I measure body fat? Measuring once every 4–8 weeks is sufficient for tracking meaningful progress. Daily measurements add noise because normal fluid fluctuations can shift readings by 1–3%.

Practical checklist for accurate body fat measurement

Take measurements at the same time of day, ideally morning before eating
Measure consistently at the same anatomical landmarks each time
Use the same method across all measurements — switching methods introduces inconsistency
Track trends over 4–8 weeks rather than day-to-day changes
Combine body fat tracking with waist circumference for a fuller picture

Final takeaway

Body fat percentage gives you far more actionable information than body weight alone. Whether you use the Navy formula, calipers, or BMI-based estimates, the goal is consistent tracking over time — not a single perfect number. Use the tools below to calculate your body fat and related metrics quickly.