Body fat percentage varies by weight, height and even DNA. Everyone needs a certain amount of body fat to store energy and ensure the normal functioning of the body (for example, to keep the body temperature stable or protect the organs). You can measure your body fat at the gym or at your doctor's office, or at home using a tape measure. The United States Navy has developed a special system for accurately determining the percentage of fat mass. This is a fairly simple method to apply that allows you to get an estimate of your body fat percentage so you can set goals, stay healthy, or lose weight.
Steps
Part 1 of 3: Calculation Guidelines for Men
Step 1. Measure your neck
For men it is necessary to take neck measurements first. Follow these guidelines to make sure you proceed as accurately as possible:
- Place the tape measure just below the Adam's apple (larynx).
- Make it stick to your skin and wrap it around your neck. Don't hunch your shoulders and keep the tape as straight as possible.
- Write down this measurement in a notebook.
- For example, suppose your neck circumference is 46cm.
Step 2. Measure your abdomen
To calculate the fat mass, it is essential to take the measurements of the torso as it is an area that can contain a greater amount of fat.
- Turn the tape measure around your waist, at the level of the navel.
- Breathe in and out normally.
- Note the circumference of the abdomen after releasing the breath.
- For example, suppose it is 89 cm.
Step 3. Measure the height
The percentage of body fat also depends on the height, so this data must also be noted.
- Stand against a wall or other vertical surface.
- Keep your shoulders back, your head straight and look straight ahead.
- Use a ruler or ruler by placing it over your head and pushing it against the wall. Make a mark with a pencil.
- Stretch the tape measure from the floor to the mark you made with the pencil on the wall.
- Make a note of this measurement.
- For example, suppose your height is 1.83m.
Step 4. Enter the data correctly into the equation
Use the following formula to calculate the percentage of male fat mass:
- % Fat = 495 / [1, 0324-0, 19077 (log (waist-neck)) + 0, 15456 (log (stature))] - 450.
- Using the above examples, we get the following equation: Fat% = 495 / [1, 0324-0, 19077 (log (89-46)) + 0, 15456 (log (183))] - 450. For convenience, you can use the spreadsheet indicated on this site.
- The result should be a decimal number. In this particular example, the body fat percentage hovers around 9, 4.
Step 5. Interpret the results
The result will fall into a category that will allow you to understand if your weight is right.
- Normally, men have around 2-4% essential fat. If the percentage of essential body fat falls below this value, know that it is dangerous: fat reserves play an important role in the regular functioning and protection of the organism.
- The fat mass in athletes is equal to 6-13%, in quite fit men it is between 14 and 17%, in those on average or moderately fit it reaches 18-25%, while in overweight or obese men equals or exceeds 26%.
Part 2 of 3: Calculation Guidelines for Women
Step 1. Measure your neck
Like men, women also need to measure the circumference of the neck in order to calculate the percentage of body fat.
- Place the tape measure just below the larynx.
- Make it stick to your skin and wrap it around your neck. Don't hunch your shoulders and keep the tape as straight as possible.
- Write down this measurement in a notebook.
- For example, suppose your neck circumference is 38cm.
Step 2. Measure your abdomen
Women tend to store more fat in this area.
- Run the tape measure around your waist at the narrowest point, which is halfway between the navel and the breastbone.
- Breathe in and out normally.
- Note the circumference of the abdomen after releasing the breath.
- For example, suppose it is 71 cm.
Step 3. Measure your hips
Women can accumulate more fat around their hips than men. Therefore, by considering this measurement within your calculations, you will get a more accurate result.
- Run the tape measure around your hips so that it wraps around the fullest part of your buttocks.
- Make it adhere to the skin so that you can take the correct measurements. If you are dressed, make sure that clothing does not significantly affect sizing.
- Write this down.
- For example, suppose the circumference of the hips is 81 cm.
Step 4. Measure the height
Remember that your body fat percentage is also based on your height.
- Stand against a wall or other flat surface.
- Keep your shoulders back, your head straight and look straight ahead.
- Use a ruler or ruler by placing it over your head and pushing it against the wall. Mark this point with a pencil.
- Stretch the tape measure from the floor to the mark you made with the pencil on the wall.
- Make a note of this measurement.
- For example, suppose your height is 1.68m.
Step 5. Correctly enter the data into the equation
Use the following formula to calculate the percentage of female fat mass:
- % Fat = 495 / [1.29579-0.35004 (log (waist + hips-neck)) + 0.22100 (log (height))] - 450.
- Using the above examples, we get the following equation: body fat = 495 / [1.29579-0.35004 (log (72 + 81-38)) + 0.22100 (log (168))] - 450. For convenience, you can use the spreadsheet indicated on this site.
- The result should be a decimal number. In this particular example, the body fat percentage hovers around 14.24.
Step 6. Interpret the results
The result will fall into a category that will allow you to understand if your weight is right.
- Typically, women store around 10-12% essential fat. It is superior to that of men because the body of women is designed so that the fat mass allows them to face a possible pregnancy.
- The fat mass in athletes is 14-20%, in fairly fit women it is between 21 and 24%, in those on average or moderately fit it reaches 25-31%, while in overweight or obese female subjects equals or exceeds 32%.
Part 3 of 3: Use a Tape Measure to Determine Fat Mass
Step 1. Purchase a tape measure
When you need to test at home, you need to have a measuring tape handy.
- You might want to buy a fiberglass tape measure. If you want to get more accurate results, it should be made from a material that doesn't stretch.
- Make sure the tape measure is correctly graduated. Compare it to a regular ruler or folding ruler.
Step 2. Be careful when taking measurements
When you intend to calculate your body fat percentage with a tape measure, you need to know how to use it correctly to get the most accurate results.
- When taking your measurements, make sure the tape fits your skin: it must follow the shape of your body. Squeeze it, but not tight enough to compress it.
- The most common mistake is to use an unsuitable tape measure or to be inaccurate in the measurements.
Step 3. Check the measurements 3 times
If you want to get more accurate results, keep in mind that each measurement must be taken 3 times.
- Write down each measurement in your notebook. Round off to get closer to the nearest digit.
- It is preferable to take a whole series of measurements (waist, hips, neck, arms) instead of determining the circumference of the waist 3 times, of the hips 3 times and so on.
- After measuring each body part 3 times, calculate the average and use this figure in the fat mass equation.
