What is Body Fat Percentage?
Body fat percentage is the proportion of fat in the body relative to total body weight. Unlike BMI which only measures weight relative to height, body fat percentage provides a more accurate picture of body composition. The human body needs fat for essential functions such as storing energy, protecting vital organs, and supporting hormonal function. However, too much fat (obesity) increases the risk of heart disease, diabetes, and hypertension. Conversely, too little fat (especially in women) can disrupt reproductive function and hormone balance.
Navy Method (Most Practical) Formula
Men: BF% = 495 / (1.0324 - 0.19077×log(waist-neck) + 0.15456×log(height)) - 450Formula: Women: BF% = 495 / (1.29579 - 0.35004×log(waist+hip-neck) + 0.22100×log(height)) - 450Variables:
- BF%Body Fat PercentageBody fat percentage(e.g.: 18%)
- WaistWaist CircumferenceIn centimeters (cm)(e.g.: 85 cm)
- NeckNeck CircumferenceIn centimeters (cm)(e.g.: 38 cm)
- HipHip Circumference (Women)In centimeters (cm)(e.g.: 95 cm)
- HeightHeightIn centimeters (cm)(e.g.: 175 cm)
Categories:
How to Use the KalkuLab Body Fat Calculator
- 1
Select Gender
Choose male or female (formula differs by gender).
- 2
Enter Measurements
Enter height (cm), waist, neck, and hip (women only) circumferences in cm.
- 3
Calculate
Click calculate to get body fat percentage and category.
- 4
Review Category
Compare your result to fitness/health categories for your gender.
💡 Tip:
- •Measure waist at navel level
- •Measure neck below the larynx
- •Use a flexible tape measure
- •Navy method is an estimate—not as precise as DEXA scan
Examples
Example: Male Body Fat
Male: height 175 cm, waist 85 cm, neck 38 cm.
- 1.Enter measurements
- 2.Apply Navy formula for males
Falls in the fitness category for men.
Example: Female Body Fat
Female: height 165 cm, waist 70 cm, neck 32 cm, hips 95 cm.
- 1.Enter all four measurements
- 2.Apply Navy formula for females
Falls in the fitness category for women.