How to Calculate Your Body Fat Percentage

Measure your waist circumference using a tape measure. Waist measurements can help assess your risk of certain health conditions, such as those associated with excess weight or obesity. Specifically, if most of the fat is stored around your waist (known as abdominal fat) rather than your hips, there is a higher likelihood of cardiovascular diseases and other health issues. To measure your waist accurately, stand upright, wear only underwear, and wrap the tape measure around the lower part of your abdomen, just above the hips and below your navel. Breathe in, and then measure your waist just after exhaling.

• When measuring your waist, use the tape measure to wrap it snugly around your waist, but avoid pulling it too tightly into the soft tissue beneath.
• If your waist circumference exceeds 90 cm for women or 102 cm for men, you may be at a higher risk of health issues.
• Another method is the U.S. Navy’s formula, which estimates body fat percentage by considering waist, hip, and neck measurements alongside height and weight.

Use Calipers to Measure Body Fat. The caliper method, also known as the skinfold test, involves pinching the layer of fat under the skin away from the muscle at specific points on the body and measuring the thickness of the skinfold using the calipers. These measurements are then converted into an estimated body fat percentage using a specific formula. Typically, only three measurements are needed, whereas other methods might require up to seven. While this method may not provide a perfectly accurate body fat percentage, it is a reliable way to track changes in body composition over time (with an error margin of approximately 3%). However, this margin of error may be higher for very lean or very obese individuals. You can ask a friend or family member to help, or visit a fitness club, medical clinic, or hospital for assistance.

• When using the calipers, apply consistent pressure at all measurement points.
• It’s recommended to have a professional perform the measurement for better accuracy.
• Estimating body fat from skinfolds depends on the type of caliper and the technique used. However, this method only measures one type of fat: subcutaneous fat.

Measure Bioelectrical Impedance. Bioelectrical impedance is a method used to assess body fat by measuring the resistance of fat tissue to an electrical current. Fat does not conduct electricity well, while muscle and bone tissue do (though weakly). This technique measures the electrical resistance of fat compared to other tissues in the body. The results from bioelectrical impedance are about 95% accurate, depending on factors such as the water content in your body, which can fluctuate based on exercise, diet, sweating, hydration levels, and alcohol or drug use. The advantage of this method is that it doesn’t require an expert, and the equipment is generally not expensive. Many gyms and physical therapy centers have these machines available, often for free.

• You can either stand barefoot on a metal plate that sends an electrical current through your body (similar to a regular scale), or hold a handheld device (with both hands) to transmit the current through your body.
• For the most accurate results, avoid eating for 4 hours before the test, refrain from intense physical activity for 12 hours, and avoid alcohol or diuretics (including caffeine) for 48 hours before the test.

Calculate Your Body Mass Index (BMI). BMI is a valuable tool for identifying whether you are overweight or obese, and assessing your risk of health conditions like heart disease, high blood pressure, type 2 diabetes, and other issues. It is calculated based on your height and total body weight, and serves as an estimate of body fat in relation to other body tissues. To calculate your BMI, divide your weight (in kg) by your height (in meters) squared. The higher the result, the greater your risk of health problems. A normal BMI ranges from 18.5 to 24.9; between 25 and 29.9 is considered overweight, and 30 or higher is classified as obese, which is quite risky.

• This method works for most men and women, but has some limitations. For example, athletes and people with more muscle mass may have a higher BMI, while older adults or those with less muscle mass may have a lower BMI.
• To get a more accurate estimate of body fat percentage, use the following equation with your BMI: (1.20 x BMI) + (0.23 x Age) - (10.8 x Gender) - 5.4. For males, gender is 1, and for females, it is 0.

DEXA Scan Method. If you want an accurate body fat percentage calculation, you should consider getting a test at a facility with a Dual-Energy X-ray Absorptiometry (DEXA) scanner. The DEXA scan uses X-ray technology to estimate muscle tissue, bone mineral density, and fat tissue in all regions of the body with high precision. The scanner combines two X-ray beams to assess body composition in different areas, allowing you to identify which parts of your body have the highest fat percentage (or the most muscle). The scanner works similarly to the TSA body scan at airports, emitting a small amount of radiation through your body. The DEXA scan is considered the gold standard for measuring body fat percentage across the entire body, as well as specific areas like arms and legs.

• Unlike MRI or CT scans, a DEXA scan doesn't require you to be enclosed in a tight tunnel. Instead, you lie flat on a table, and the X-ray scanner slowly passes over your body – typically, the procedure takes less than five minutes, though the duration depends on the body part you're having scanned.
• Many large universities (in physiology labs) and healthcare facilities have DEXA scanners. You can ask your doctor to recommend a local facility with DEXA scanning capabilities. The primary purpose of the device is to measure bone mineral density. The cost of a DEXA scan ranges from $100 to $200 if it's not covered by your health insurance.

Underwater Weighing. Since muscle and bone tissue are much denser than fat, determining body density is an effective way to assess body composition. The underwater weighing method involves diving into a water tank (which has water level markings), and the displacement in the water level before and after you dive is used to calculate tissue density and overall body fat percentage. The greater the displacement, the more likely you have bone and muscle tissue, thus a lower fat percentage. Underwater weighing (or hydrostatic weighing) is an extremely accurate method for calculating body fat, with a margin of error as low as 1.5% when performed correctly.

• The main downside of this method is that it requires you to be submerged in water and fully exhale while holding your breath for a few seconds.
• Athletes tend to have a higher bone and muscle tissue density compared to non-athletes, which means this method may underestimate their body fat percentage.
• Consult with a doctor or search for local healthcare or research facilities that offer underwater weighing. However, this method may not be widely available. Additionally, compare the costs of this method with those of a DEXA scan before making a decision.

Near-Infrared Interactance (NRI) Measurement. This method measures body fat by using the principles of light absorption, reflection, and near-infrared spectroscopy. A specialized device called a spectrometer with a handheld probe is used to estimate body fat composition. The probe is placed on a part of the body (usually the upper arm), emitting infrared light that passes through fat and muscle, reaching the bone, and then reflects back into the probe. The measured density is applied to a predictive equation that includes height, weight, and body type to estimate the overall body fat percentage. While not as precise as DEXA or underwater weighing, the NRI method provides more accurate results than home-based methods like skinfold calipers or bioelectrical impedance analysis.

• The NRI method tends to be less accurate for individuals with extremely lean muscles (body fat percentage <8%) or those who are obese (body fat percentage >30%).
• Results may vary depending on the pressure applied to the probe, skin tone, and body moisture levels, making them less reliable.
• NRI devices are commonly found in many gyms, health clubs, and weight loss centers, and they are relatively affordable, or sometimes even free. Physical therapy clinics may also have NRI equipment available.