There are different answers to the question "How is body fat calculated?" The most scientifically accurate methods for calculating body fat percentage are usually used in research facilities and universities, but these can be on the expensive side, and in many cases, they aren't even open for public use.
You can always opt for other methods such as skinfold calipers, body circumference measurements, smart scales, and waist circumference.  These are all methods you can use at home regularly to give you a general idea of your body fat levels.
Yes, the same kind used for wood and metalwork, can be used to measure the thickness of your subcutaneous fat underneath the skin. A common procedure for taking skinfold measurements is the seven-point method, where you take measurements by pinching seven parts of the body, including the triceps, under the shoulder blade, chest, midaxillary (near the armpit), above the hip, abdomen, and thigh.
It takes some skill and experience with anatomy for this method to produce accurate results. The accuracy of skinfold calipers can also vary depending on how consistently you measure the same spots.
This method involves taking circumference measurements at specific parts of the body and getting the averages. Body fat percentage is then calculated by plugging the figures into an equation. It is recommended that men take measurements around their necks right below the voice box and around the waist at the navel. Make sure you don't squeeze your stomach in so you can get a true reading. You should also keep your neck from stretching out too far.
This method is an even simpler variation on the body circumference method, where you can check your midsection's body fat by measuring just your waist circumference. A waist circumference measurement can help you figure out if you have too much fat around your midsection. Keeping a waist circumference below 94 cm is recommended by the World Health Organization for most men. However, your overall body fat percentage cannot be determined with this method.
Foot-to-foot impedance meter (FFI)
For smart scales, also called body fat scales, body composition is measured using a foot-to-foot impedance meter (FFI). Compared to other tissues and substances in the body, body fat is particularly resistant to electricity. FFI measures the resistance that the body has to a very weak electrical current that it sends through. Thus, the presence of higher resistance indicates a higher body fat percentage.
Accuracy varies on the scales, as our hydration levels can affect how body fat percentage is calculated, but their ease of use makes them a very convenient home method for measuring body fat.
Consult your doctor if you are curious or concerned about your body fat percentage. They can explain your results and give diet and fitness advice to help you reach your fitness goals. At Mosh, we connect you with doctors who can answer your questions like "How is body fat calculated?" or ‘How to plan a diet to lose weight? remotely through SMS, chat, or video call.
Unlike some of the options that may appear when you look up "How is body fat calculated?" online, every body fat measurement tool you need for the methods listed above is easy to find and maintain without breaking the bank.
A caliper - digital or manual - is all you need for the pinching method. For the circumference measurement techniques, make sure to use a non-stretch tape measure and be careful not to squeeze too hard around the skin to the point where it compresses. Smart scales may vary in accuracy depending on the model and manufacturer.
Most methods that produce the highest accuracy, like DEXA, hydrostatic weighing, or the Bod Pod (air displacement), are usually done in labs and universities that aren't open to the general public. What's more, even when they are available at a testing facility, they can be quite expensive.
Consider the reasons why you want to determine your body fat percentage. Think about how often you aim to perform the procedure, whether you can do it at home or on the go, whether you can do it alone or with a companion, and how much emphasis you should put on precision.  Then you can choose the right method and tool for you.
When you search for "How is body fat calculated?" in a search engine, some online resources can do the math for you based on the measurements you input. Many of these calculators are based on a combination of the body mass index (BMI) and the US Navy body fat formula. 
The traditional BMI only looks at the total weight of the body. It doesn't take into account the amount of body fat or muscle mass. It only tells you how much your weight is compared to how tall you are, so it's not a very good way to determine if you're healthy or not. A person with a lot of muscle, for example, might have a low body fat percentage but a high BMI.
Focusing too much on questions like "How is body fat calculated?" and "How to lower body fat percentage" can keep us too fixated on achieving a specific number instead of our real goals. If you think of your BMI and body fat measurements as just one possible way to track your progress instead of as targets, then you may be less likely to get stuck on the numbers. 
There can be variations in different body fat levels among different age groups, sexes, and ethnicities. That's why our online weight loss questionnaire at Mosh takes those factors into account. Unlike your average body fat percentage calculator, the results of our quiz can be accessed by our doctors, who can use them to make personalized recommendations and, if necessary, provide you with a treatment plan.
Mosh is a telehealth platform that specialises in taboo-breaking issues like mental health, sexual health, weight, hair loss, and skincare. At Mosh, there is no such thing as an issue too awkward to be taken seriously. With us, you won’t have to deal with the hassles of long commutes and waiting rooms.
For doctor-backed advice on maintaining a healthy figure, talk to us at Mosh.