Body Fat Calculator

Calculate Your Body Fat & Lean Mass Instantly

Use our free Body Fat Calculator to estimate your body fat percentage using the U.S. Navy Method. Enter your gender, age, weight, height, neck, waist, and hip measurements (for females) to get a complete breakdown of your body composition, including lean body mass, fat mass, and recommended fat loss to reach ideal body fat.

What is Body Fat?

Body fat is the total mass of fat divided by total body mass. It is composed of essential fat and storage fat. Essential fat is necessary to maintain life and reproductive functions, while storage fat accumulates in adipose tissue. Knowing your body fat percentage gives a better insight into your health than weight alone.

Why Use a Body Fat Calculator?

• ✔️ Evaluate your fitness level
• ✔️ Set realistic weight loss goals
• ✔️ Monitor lean mass vs fat mass
• ✔️ Improve your overall health tracking

How to Use the Body Fat Calculator

1. Select your gender (male or female).
2. Enter your age in years.
3. Provide your weight in kilograms (kg).
4. Input your height, neck, waist, and (for females) hip circumference in centimeters (cm).
5. Click the “Calculate” button to get results instantly.

U.S. Navy Method Formula

For Males:

Body Fat % = 495 / (1.0324 - 0.19077 × log10(waist - neck) + 0.15456 × log10(height)) - 450

For Females:

Body Fat % = 495 / (1.29579 - 0.35004 × log10(waist + hip - neck) + 0.22100 × log10(height)) - 450

Example Calculation

For a 23-year-old male:

• Weight = 70 kg
• Height = 178 cm
• Neck = 50 cm
• Waist = 96 cm

Using the formula, the estimated body fat percentage = 15.7%. This falls into the Fitness category.

Body Fat Classification

What is Lean Body Mass?

Lean Body Mass (LBM) is the amount of weight you carry on your body that isn’t fat. It includes muscles, bones, water, and organs. LBM is calculated by subtracting fat mass from total body weight.

What is Ideal Body Fat?

Ideal body fat varies by age, gender, and body type. Athletes and highly active individuals may have lower body fat levels than the general population. For men, an ideal range is typically around 8–18%, while for women it's around 18–25%.

How Much Fat Should I Lose?

Based on your current fat percentage and ideal body fat range, our calculator also shows how much fat mass (in kg) you would need to lose to reach your target. This helps in setting smart and achievable fat-loss goals.

Body Fat by BMI (Alternative Method)

While BMI doesn’t directly measure fat, it can be used for approximation:

BMI-Based Formula (for men):

Body Fat % = 1.20 × BMI + 0.23 × Age - 16.2

BMI-Based Formula (for women):

Body Fat % = 1.20 × BMI + 0.23 × Age - 5.4

This BMI-based method is less accurate than Navy Method but still useful if tape measurements aren’t available.

FAQs

Can I use this calculator for weight loss tracking?

Yes. It’s great for seeing changes in fat mass vs lean mass when paired with a good diet and exercise plan.

Is the U.S. Navy method accurate?

Yes, it's considered highly accurate for estimating body fat using circumference measurements.

Is this calculator mobile-friendly?

Absolutely! It is fully responsive and works smoothly on all screen sizes including phones and tablets.

What units does it support?

All inputs are in metric units: kilograms (kg) for weight and centimeters (cm) for circumference.

Disclaimer

This Body Fat Calculator provides a close estimate based on mathematical models. It is not a replacement for clinical or medical assessments. Always consult a healthcare provider for professional advice.

Start Tracking Your Fitness Today

Whether you're a fitness enthusiast, athlete, or on a weight-loss journey, this free Body Fat Calculator from GuideCalculator.com can help you understand your body better and make smarter health decisions.

Try it now and take control of your body composition goals!