Finding your body-fat percentage is an imprecise endeavor.
The methods that we generally have available to measure it range from being ‘acceptably accurate’ to ‘very poor,’ and they are nearly all useless for tracking changes over time. They’re all marketed as being really accurate of course, but that’s just because people are after your dollars.
The lack of a guide on this site to help you find this has been something that has bugged me for some time.
On the one hand, I recommend that people do not try to track their body-fat percentage because of the errors of all the devices we have available to estimate it. On the other hand, I use body-fat percentages in my guide to helping people decide when to cut and bulk.
This guide US Navy body fat calculator combined with my new visual guide to body fat percentage fills that void.
The Issues Of ESTIMATING BODY-FAT PERCENTAGE
Here’s a rundown of the methods we typically have available to us for measuring body fat, from most to least accurate. The numbers given are the individual error rates that have been observed:
- Autopsy
- DEXA scan. ~5%
- The US Navy Body Fat Calculator ~3–4% (Convenient, free.)
- BodPod / Underwater weighing, Up to 5–6% (Expensive, inconvenient.)
- Body-fat caliper measurements. Skilled practitioner, ~3%. Non-skilled practitioner ~5%.
- Bioelectrical Impedance Analysis (BIA) machines. Up to 8%.
So, if you use a BIA machine and get a reading of 20%, your actual body fat could be anywhere from 12–28%. If you use the US Navy body fat calculator and get a reading of 20%, your actual body fat could be anywhere from 17-23%. This is the difference between being useless and helpful.
Here’s that US Navy body fat calculator formula. Take a look and then we’ll get into some practical recommendations.
The US NAVY BODY FAT Calculator
(For Men)
MEASUREMENT GUIDELINES For The Calculator
- Height – Get someone else to do it for you if possible.
- Stomach – Measure at the navel. Have a relaxed stomach, exhaled but, don’t forcefully push it out!
- Neck – Keep your head straight, look forward. Keep your shoulders down and relaxed.
- Measure three times for each and average the three.
Simple as that.
Things To Watch Out For When Measuring Body Fat
The US Navy body fat calculator wins out on convenience and cost, this is what I’d recommend for most people. Notice that the reading is heavily determined by the measurement at the navel. Two important things to point out in regards to this:
- Fat comes off of the stomach/torso generally from the top down. Past the point of 10% body fat, the mid-stomach measurement (that at the navel, which the equation uses) will change very little as the person gets leaner because most of the fat is coming off from the lower abs and back at this point. Therefore, if you’re already very lean, this won’t work well for you. It will be best to estimate from pictures or use calipers.
- It will give those with particularly thick (well developed) abs, or a bloated abdomen higher readings than reality.
Navy Body Fat Calculator FAQ
The US Navy body fat calculator is accurate to approximately 3–4%.
You can estimate your body fat percentage visually, using the US Navy body fat calculator, a BIA machine, BodPod, underwater weighing, body-fat caliper measurements, or DEXA scan. All have their flaws. I don’t recommend you try to rely on these to track your physique progress. I recommend people use scale weight and a tape measure to track progress instead.
Abs will start to show between 8% and 16% body fat, with most trainees somewhere in the middle of that range. In general, the more muscle mass you carry, the higher the body fat percentage your abs will show because you have more muscle pushing on the skin.
Body-fat percentage = 163.205 x log10(waist + hip – neck) – 97.684 x log10(height) – 78.387
Yes, you may be right. If you believe that you have a better measurement from elsewhere, then by all means, please use that. Remember, this is not being suggested as a method of tracking your progress (here is my recommendation on how to track your physique progress), but just a way to gauge where you might currently be at.
Here is the full US MoD paper covering how the formulas for the US Navy body fat calculator were developed so you can make your own decision.
Visually. Check out my visual guide to body-fat percentage.
Hope this was helpful.
Questions welcomed in the comments. – Andy
Please keep questions on topic, write clearly, concisely, and don't post diet calculations.
Privacy policy.
Hi Andy – great website and resources. I’m guessing the best time to take the measurements is first thing in the morning before any meals, but I’m curious if that’s what the Navy test is based on (were their measurements for this test taken at a certain time under specific conditions?). Can you confirm?
Hi Jonathan, thank you for the question.
I have no idea, but the difference will only be 1-2 cm regardless of the time of day you take it. So for the purposes of getting an estimation, it’s good enough and I wouldn’t worry about it.
Protein requirements? Results?
Andy,
I have a question about the longevity of my goal of 8%. It shows on one of the articles that my protein recommendations are around 160g.
If I only eat 120-140 a day and keep under my calories requirements—will this make any difference in my over body fat%? I am working on a lifetime habit of eating, not just a way to get there and then change. If it takes me 2 months longer eating less protein and I still make it to my goal I don’t care. I want to be able to maintain and keep my lifestyle for the long haul?
Thank you so much for this site and your guidance!
You’re truly a blessing.
Hi Danny,
You can see from the sketch in my article on how to set macros that protein requirements when cutting are higher than when at maintenance or bulking.
So, you don’t have to eat 160 g of protein per day to be able to maintain your physique once you’re happy with where you are at.
Roger that! Thank you sir
What is the estimated BF% of the guy at the top of the article?
Thank you sir! This website is amazing!
Hi Danny, I’d guess 7–8%. More examples in photos (but of clients) here: A Visual Guide To Estimating Body-fat Percentage.
Thank you sir
Congratulations Andy, I have a question, the abdominal circumference in the formula of women is also taken by the navel just like men or does it change to the waist circumference, the narrowest Part? Thanks
I believe it’s at the navel.
Is skinny fat real and if so what percent do you need to be in order to be considered skinny fat
Hi Gordon,
I use the term “skinny fat” to describe the muscle development and fat mass that some people carry. The purpose of the categorization is to then advise people on what to do from there. I’ve written about it here: Should I Bulk vs Cut? The Definitive Guide.
This is very useful, would you say it doesn’t matter how accurate this actually is? Isn’t what matters that you are consistent with your measurements to compare with the previous ones?
Hi George.
I’d use this only to get a ballpark figure, in conjunction with my visual guide, to aid you in deciding whether to bulk vs cut (or recomp).
I wouldn’t use this consistently over time to track progress, but I would advise multiple measurements in conjunction with tracking scale weight and a few other things. Here’s my guide to tracking progress.
Hi Andy,
I am a 30 yo female, 5’7, approx 130lbs. I do strength and cardio every day. Navy method says my body fat % is 13.3, BMI method says 25.5. Do you think I would fall somewhere between the two? Thank you!
Probably. I wouldn’t focus on body fat percentage though.
Given the issues with attempting to estimate it, I updated the calorie and macro calculator so that it’s no longer a requirement to know it. You can gauge progress with a tape measure and scale weight. Full details here: The 8 Ways I get Clients to Track Progress
I am a 64 year old male. I workout hard 5,6 days a week. Dropping body fat Is getting more and more difficult. I want to eat enough to fuel my workouts, but not to much so I can drop body fat. Everything is changing in my 60’s and I can’t find current data for my population
Hi Mick,
To drop body fat you need a caloric deficit. To do that, you need to start with a calculation. Use this calculator (it has an age factor), it will give you a rough start point. Make sure you read the notes section below it.
i used a website that had both the navy calculator and the bmi calculator and i’m just wondering which one is more accurate? The navy calculator said i have 21.6% body fat, but the bmi calculator said i have 28% body fat, which one do i go with?
Navy.
I used a BIA and my body fat is at 30.6%.
I added light weight training about 2-3 weeks ago and it seems like I am losing muscle mass.
The results also showed that my trunk fat percentage is the highest even though it has slimmed down.
Do the exercises for the beginner 3 help in reducing fat percentage at the trunk?
And am I eating too little?
My BKR is roughly 1162 cal. I exercise an hour 5 times a week and consume about 1400-1500 cal a day.
Thank you!
You’re not, the machine is shit. That’s kinda the point of this article — ignore it and track your progress like this.
Based on the us navy calc, i am 23% BF (female) which i believe most of it is at my belly because i can pinch a huge amount of skin/fat from my belly.
I’ve been doing several abs exercises and have seen improvements over the month. Cardio 4 times a week. The line is more define.
Unfortunately i have not been able to stick to my daily protein intake. (I will be cooking soon so i hope I can make my meals meet the requirements daily). Added some resistance training the past 3 weeks. Going to do more resistance and heavier training from now on.
Do i need to be in a cal deficit to put on muscle but lose body fat?
Thank you so much!
Hi Row,
You can’t spot reduce body fat by working a specific muscle in that area. So, doing crunches will not help you lean out your stomach, but it will develop your ab muscles. This is because fat is released globally from the fat stores around the body into the bloodstream, sent around the body to be used in tissues where it’s needed, and burned off as fuel.
To drop fat, create a small caloric deficit, strength train. You’ll lean out and gain muscle. This article (The Complete Nutrition Setup Guide) will be helpful.
Thanks for your help!
Yes I read it but was kind of confused if I should have a cal deficit or maintain the same.
But you just answered it. Thank you so much for your advice! I’m excited and hope to see results in a few months’ time 😀
Most welcome!
Andy, just used the body fat chart and came up with 19% (not good) but weighing only 155# at 5’10” tall I feel underweight any suggestions ?
If you’re relatively new to serious training, just train hard and eat at caloric maintenance and you’ll gain muscle and lose fat. Make sure you take stomach measurements as per this guide though so you have data on the changes.
Hi Andy
Is there a Source for the SEE values you listed for the different methods? And im Not sure if i misunderstand what you Are saying But if the BIA from a commercial gym has a 8% error i Would expect the 20% to be off By up to 2% Not 8. (20×0,92=18,4 or 21,6)
thanks in advance
You’ll find the references in James Krieger’s articles. Just google “James Krieger body fat percentage” + whatever method of bf% testing you wish to see destroyed comprehensively.
Hi Andy,
Came across your site a few days ago. Its excellent!
I have a question: I have been cutting since May and have lost 5kg. My daily calories are 2020. When I used your metric calculator it said I should be consuming 2629 calories. What should I do? Switch and maybe put the weight back on I have already lost or wait until I go back into my bulk phase in September before switching?
Thanks!
Hi Adam, see the second answer in the FAQ.
THANK YOU! Your writing and level of expertise is exactly what I have been looking for, for basically my whole life. Thank you for being so generous with your knowledge, tools, and experience.
Most welcome, Devan.
Do you measure above the belly button or below
At the belly button.
Hi,
For the calculation for women: are the measurements of neck, waist etc to be entered in the metrical or imperical system?
So inches or centimeters :)! Thanks!
Imperial
Andy,
I have been dieting and lifting for over ten years, but this was the first time I’d seen the Navy approach mentioned. (I can’t tell you how many times I’ve read words similar to “All body fat measurement approaches suck. Just use the same one so your results will suck consistently.”) The results were in the ballpark I’d expected (19%), although your explanation that measuring the neck and abdomen makes the most sense because that’s where most people store fat was a lightbulb moment. I can’t thank you enough for providing such an excellent resource.
Bill
Most welcome, Bill.
You’ve probably picked up on this from the article, but in case not, “Just use the same one so your results will suck consistently.” is incorrect also.
Hello Andy,
I was reading through this article and saw that you mention bloating as throwing off measurements.
What would you recommend for someone who wakes up bloated most mornings and takes measurements?
Consistency is the most important thing. So, if it’s the same every day at that time of day it won’t matter.
I am 18.1% body fat without having committed to any gym program for a few years. What would be considered a healthy fat percentage without considering aesthetics of ripped lean muscle?
I’m not sure it’s possible to put a figure on this, but the leaner you are the better the blood markers for disease risk tend to be with diminishing returns. I doubt there would be much difference for people in the 11-14% body fat range.
Hi Andy,
Do you have a reference for your BF% equations?
Thanks in advance,
Linn
Sure. You’ll find them all in James Krieger’s series on bf% measurement issues here.