Last Updated: April 9th, 2020
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 method 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 Equation ~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 equation 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 formula. Take a look and then we’ll get into some practical recommendations.
US NAVY METHOD OF BODY FAT ESTIMATION
(For Men)
MEASUREMENT GUIDELINES
- 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
The US Navy equation 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.
ANTICIPATED QUESTIONS
Do you have the calculation for women?
Sure thing. I didn’t include it because 86% of the site’s readers are men. Here’s the imperial calculation:
- Body-fat % = 163.205 x log10(waist + hip – neck) – 97.684 x log10(height) – 78.387
This looks inaccurate for me…
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, but just a way to gauge where you might currently be at.
If you’d like to read the full US MoD paper on the way the formulas were developed so you can make your own decision, you can get that here.
How do you gauge body-fat percentage when setting things up for clients?
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.
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.
Andy, all of your articles are extremely well written and full of great information. Definitely the most precise and enjoyable online coaching I’ve came across thus far. Thank you for your dedication!
Thanks for writing, A Rog. 🙂
PS: Sorry for the delay in replying. I had been unable to do so while the website went through a big update over August.
I can vouch for this calc. I had a DEXA scan and this calc was within 0.3% !
So, if you are a man with a typical fat distribution in the torso it is as accurate as DEXA and free !
Hi Andy,
For an optimal nutrition partitioning in realizing muscle mass, what bodyfat % do you recommend? Max 15%? for men?
Is this also a issue for women? If so, whats the maximum bodyfat %?
For men 10% bodyfast is pretty ripped, what is the equivalent for women?
Thanks in advance Andy.
Hi Teun, thanks for the questions. In order:
– The leaner the better, down to around 9-10%. Beyond that there is probably little benefit.
– Yes. / There is no maximum, it’s in degrees.
– Add 8%.
What does the ~ 3 % mean for the us navy method does that means add three to your bf percentage
Hi Seif, that’s the standard error of estimate (SEE), which basically means how accurate it is for most people. You can expect your estimate to be within 3% of your actual body fat percentage. Thank you for asking, I’ll rewrite them as ~3% to ~3%(+/-) which will be clearer.