Body Fat Calculator - Body Fat Percentage Calculator & Body Composition Calculator
Free body fat calculator to estimate your total body fat based on specific measurements. Calculate body fat percentage using U.S. Navy method and BMI method. Use the "Metric Units" tab if you are more comfortable with the International System of Units (SI). To get the best results, measure to the nearest 1/4 inch (0.5 cm).
Last updated: February 2, 2026
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Below the larynx, tape sloping downward to the front
At navel level
Body Fat Results
Body Fat
15.7%
Body Fat (U.S. Navy Method)
15.7%
Body Fat Category
Fitness
Body Fat Mass
11 kg
Lean Body Mass
59 kg
Ideal Body Fat for Given Age (Jackson & Pollock)
10.5%
Body Fat to Lose to Reach Ideal: 3.6 kg
Body Fat (BMI method)
16.1%
Measurement Tips:
- • Measure to the nearest 1/4 inch (0.5 cm) for accuracy
- • Don't pull stomach inwards when measuring waist
- • Results are estimates; for accuracy use bioelectric impedance or hydrostatic testing
Body Fat Categories
Quick Example Result
For a 25-year-old male with height 178 cm, weight 70 kg, neck 50 cm, and waist 96 cm:
Body Fat (U.S. Navy)
15.7%
Category
Fitness
Body Fat Mass: 11.0 kg | Lean Body Mass: 59.0 kg
How the Body Fat Calculator Works
The Body Fat Calculator uses two methods to estimate your body fat percentage: the U.S. Navy method and the BMI method. The U.S. Navy method is based on equations developed at the Naval Health Research Center by Hodgdon and Beckett in 1984, using measurements of neck, waist, and hip (for women) circumferences along with height and weight.
U.S. Navy Method Formulas
For Males (USC Units):
BFP = 86.010×log₁₀(abdomen-neck) - 70.041×log₁₀(height) + 36.76
For Females (USC Units):
BFP = 163.205×log₁₀(waist+hip-neck) - 97.684×log₁₀(height) - 78.387
For Males (Metric Units):
BFP = 495/(1.0324 - 0.19077×log₁₀(waist-neck) + 0.15456×log₁₀(height)) - 450
For Females (Metric Units):
BFP = 495/(1.29579 - 0.35004×log₁₀(waist+hip-neck) + 0.22100×log₁₀(height)) - 450
The calculator automatically handles unit conversions and provides results in percentage. Measure to the nearest 1/4 inch (0.5 cm) for best accuracy.
Measurement Instructions
To get accurate results, follow these measurement guidelines:
- Neck: Measure below the larynx (Adam's apple), with the tape sloping downward to the front. Avoid flaring your neck outwards.
- Waist (Men): Measure at a horizontal level around the navel. Don't pull your stomach inwards.
- Waist (Women): Measure at the level with the smallest width.
- Hip (Women only): Measure at the largest horizontal measure around the hips.
- Accuracy: Measure to the nearest 1/4 inch (0.5 cm) for best results.
BMI Method
The BMI method estimates body fat percentage based on BMI, age, and gender:
- Adult Males:BFP = 1.20 × BMI + 0.23 × Age - 16.2
- Adult Females:BFP = 1.20 × BMI + 0.23 × Age - 5.4
- Boys:BFP = 1.51 × BMI - 0.70 × Age - 2.2
- Girls:BFP = 1.51 × BMI - 0.70 × Age + 1.4
Body Fat, Overweight, and Obesity
The scientific term for body fat is "adipose tissue." Adipose tissue serves important functions: storing lipids for energy, secreting hormones, and providing cushioning and insulation. Body fat includes essential body fat (necessary for life and reproductive functions) and storage body fat (accumulated in adipose tissue).
Essential body fat is typically 2-5% in men and 10-13% in women. The healthy range of body fat for men is typically 8-19%, while for women it's 21-33%. While excess body fat can have detrimental health effects, insufficient body fat can also have negative health effects, and maintaining body fat below essential levels should be discussed with a medical professional.
Limitations & Accuracy
The results of these calculations are only estimates since they are based on many different assumptions to make them as applicable to as many people as possible. For more accurate measurements of body fat, consider using instruments such as bioelectric impedance analysis (BIA), dual-energy X-ray absorptiometry (DXA), or hydrostatic density testing.
Sources & References
- Hodgdon JA, Beckett MB. - Prediction of percent body fat for U.S. Navy men and women from body circumferences and heightNaval Health Research Center, 1984
- American Council on Exercise - Body Fat CategorizationStandard body fat percentage categories for men and women
- Jackson AS, Pollock ML. - Generalized equations for predicting body density of menIdeal body fat percentages by age and gender
Need help with other health calculations? Check out our BMI calculator and calorie calculator.
Get Custom Calculator for Your PlatformBody Fat Calculator Examples
Input Values:
- Gender: Male
- Age: 25 years
- Height: 178 cm
- Weight: 70 kg
- Neck: 50 cm
- Waist: 96 cm
Calculation Steps:
- Apply U.S. Navy formula for males (metric)
- BFP = 495/(1.0324 - 0.19077×log₁₀(96-50) + 0.15456×log₁₀(178)) - 450
- Calculate logarithms and solve
- Result: Body Fat = 15.7%
- Category: Fitness (14-17% for men)
Result: Body Fat = 15.7% (Fitness Category)
Body Fat Mass: 11.0 kg | Lean Body Mass: 59.0 kg | Ideal Body Fat: 10.5%
Female Example
30-year-old female, 165 cm, 60 kg
Body Fat: ~22% (Fitness category)
BMI Method Comparison
Same person using BMI method
Body Fat: ~16.1% (slightly different)
Frequently Asked Questions
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