US Navy Calculator - Body Fat Calculator

Jason   I am currently in the navy and a fitness leader. To answer people questions. There is information at the top and tells you its a estimate not the actual percent no it doesn't count lean mass or water weight. If you really want to know go and have a water test done and that is the best you can do. - 6/6/2013 5:50:12 AM

Brandon   At 'person' who wrote: " I'm 13 years old. 5'1 100lbs. My waist is 25 inches and my neck is14 inches. It says I have 2% body fat, 2 lbs fat mass, and 98 lbs lean mass." I can guarantee that you do not have a 14 inch neck. most likely you have somewhere around a 12 inch neck. This would put you at 9% bf. I say this becouse when iwas 13 I was 5'3" 130 lbs with a 13 inch neck. I also had 15% bf. And still do but with a 17 inch neck 5'8" 192lbs - 5/26/2013 9:37:50 AM

Lucas   The navy requires mails to be 23% body fat or under to enlist - 5/21/2013 8:55:33 PM

Gettingthere   It would appear that 'weight' is not a variable that is used in this formula, as you can change the weight that is entered, and the %body fat doesn't change. Weight is apparently only used to determine how much lean body mass/body fat that you retain, which is simply multiplying the %body fat by the weight value entered. That could be why 1derpalm is not seeing a change in %body fat, even as he loses 10 lbs. If the inches are static, so will the body fat. - 5/6/2013 5:17:33 PM

Adamo   I disagree with Brandon that "These formulas dont differentiate between fat mass and lean body mass". In fact if you look at the Navy formula, this is exactly why the neck circumference is used. This measurement enters the formula as a negative (albeit as part of a logarithm inside a quotient) which utilises the relationship between waist and neck size. This is intended exactly to exploit the fact that the neck is a part of the body where very little of the body's fat is stored, and the waist is a part of the body where a significant proportion of the body's fat is stored. It isn't perfectly precise, but it does help the estimate to differentiate between fat mass and other sources of body mass. Nobody should expect to get accurate answers from this approach, or from the electrical impulse approach available on some weighing scales. Calipers and hydrostatic weighing are better. Worst of all the BMI method, which absolutely FAILS to differentiate between fat and other body mass. Not only that, but arguably it is not even a consistent measure of body shape because it effectively assumes the body to be 2-dimensional. The ponderal index is a better measure as it works to the power of 3. - 5/4/2013 2:44:02 PM

Person   I'm 13 years old. 5'1 100lbs. My waist is 25 inches and my neck is14 inches. It says I have 2% body fat, 2 lbs fat mass, and 98 lbs lean mass. - 5/4/2013 12:06:42 AM

1derpalm   interesting. i weighed myself at the gym after working out last night (wrong thing to do, i know), and it said 17.6 %. The guy said it usually raises or drops 2% after a workout (in terms of accuracy). this says i am at 19%, which would correlate with my guess. my scale at home has been saying 22.3 % body fat for the last 10 or so pounds that i have lost, even though i ma getting stronger and some muscle definition. i think my home scale is a bit off in that respect. - 4/20/2013 11:47:28 AM

Brandon   Hey everyone, these are indirect methods of measuring body composition. Indirect means that it isnt a direct measurement of body fat. It is a measure of how much you weigh vs. how big you are. You can be very thick because of bulging fat, and you can be very thick because of bulging muscle. These formulas dont differentiate between fat mass and lean body mass (muscle weighs 3 times more than fat.) This is why professional football players (even running backs) can have a overweight body classification, but still be world class athletes. If you are so concerned about finding out your TRUE body composition, then you should go to your doctor and request a DEXA scan, BodPod test, or Underwater weighing test, like Moss Parker said. If you dont have 200-75$ to drop on one of those tests, then you can try to find a BIA scanner in your local gym. They look like an old school nintendo controller and they try to measure body fat by sending a tiny electrical impulse from one hand, that travels up your arm, across your chest, and then back down your other arm, and then measuring it. It works on the principle that a current travels faster through water than fat, and based on norms pre programmed into the device, will spit out a more accurate result for your body fat. PLEASE REMEMBER that this still wont be as accurate as DEXA, BodPod or Underwater weighing. If you just want to know your general body fat percentage and you dont really care about knowing EXACTLY what it is and you are just trying to track weight loss, then these formula methods work fairly accurately as long as you use the same one from time to time. If anybody has any questions or wants clarification on something, feel free to respond to this and I would be happy to help if I can. - 3/25/2013 2:02:46 PM

Moss Parker   I'm a retired Naval MSC scientist (CDR). I was stationed at the Naval Subamarine Medical Research Laboratory in Groton when the three-measurement body fat index was tested. Immersion, caliper and 3-measurement methods were compared. Using immersion as the gold standard (thank you, Archimedes) what was found was that the three-measurement method performed every bit as reliably as the caliper method for most sailors, even SEALS. Of course, sailors that were well out of what of what might be considered 'normal' in regard to physical build (e.g., guys with 20" necks or women with "40" natural hips) were not measured accurately. Cumulatively over my career I was command PRT officer for over 5 years. As far as the PRT goes, I never had a problem differentiating body build from fat. We always kept a pair of calipers around, just in case. Anyway, if you are within statistical norms, the three-measurement method is an accurate measure of body fat. Oh, and by the way, when I was doing signicicant sculpting weight training, I maintained reliable body fat percentages aroung 6-7%. This was repeatedly confirmed with immersion! - 3/22/2013 3:08:57 PM

Person   for those of you coming in way low... are you measuring your waist at your natural waist, or where the waistband of your pants hits? I guarantee for men under the age of 70, these are two very different places. - 3/14/2013 9:36:51 AM

AWV2 Burgess   I don't agree with the methdo that the navy uses because no everyone has the same body type. I have a First Class who is huge but he has a fat neck so somehow he still makes BCAs. People who are pear shaped with a tiny neck, they are screwed. This is merely a comparison of averages and as stated before, if youre not average then watch out. This calculator is accurate to what the navy uses. I plugged in the numbers from 20+ sailors from out last cycle and they all came out to be exactly what our charts had. I recomment this (for NAVY use) - 1/30/2013 7:25:57 PM

Garrett   How can Lt. Meowington be 5'9 150 and have a deathly 6%, when I'm 19 years old, 5'11 130, a big time athlete, and be 11%??? Something is obviously off there. Hang in there Lt. Maybe I can lend you some percents. - 1/13/2013 4:20:28 PM

Lt Meowington   I is calling bullshit man you is talking pure bullshit. According to this ive 6% body fat which is clearly a lie 5"9 150 pounds - 12/17/2012 5:18:01 AM

Louis   well, it says im 4 %, lovely now im getting free food from everyone!! and my best friend, a personal trainer says ill be dying soon!! - 12/14/2012 3:51:21 PM

Kristina   5% if fat doesn't sounds right.. - 11/27/2012 5:04:13 AM

Fatter than this?   I'm a bit confused - every body fat percentage calculator I have used ( or used 11 so far tonight) has put my body fat percentage at 14.5-17%. I am a female, 5'4" tall, 116lbs, 24" waist, 12" neck and 33" hips. I have been told I have 97lbs lean and 19lbs fat. This doesn't make sense to me because I am not majorly thin, I am strong, but I'm no athlete (especially not recently!) and this seems much too low! I used the navy calculator because I thought it would be reliable! I am 17 which I thought may have effected it, but even calculators that take age into account have the same result! Is this correct? - 11/9/2012 2:21:26 PM

Some fatty   I hate how they do this. I'm 6'1", 240 lbs, with 38 inch waist and 17 inch neck. It gives me 20%. However, in high school, I did a lot of heavy lifting and I continued the upper body heavy lifting so according to calipers, I am at about 12%. I also have wide hips for a guy so that makes my waist "fatter". - 10/20/2012 11:44:08 AM

CE2(SCW)   Well, Ive been using this calculator for a couple years now. It pretty much pegs me around the same each time, it tells me when im over and when im not, ive failed a PRT and this told me i would, and I normally pass. So i dont see this calculator as a bad way to tell my percentage. I simply see it is as a way to tell me whether or not im going to pass my PRT, hasnt failed me yet! - 10/16/2012 7:38:38 AM

John Wright   Ha! I was categorized as Obese! I am not even considered overweight...this is very strange. - 10/10/2012 6:52:31 AM

Batman   Is the measure taken tumy tucked in flexing or flabby position (for the waist measure)? - 9/26/2012 5:48:15 PM