T Nation

Body Fat Calculator

After reading Norcross’ articles on Body Composition for Beginners, I wanted an easy way to do the calculations as described by the formulas in his articles. I checked out the links for the BF% calculators, but I thought they were garbage. They didn’t look good and they weren’t dynamic as there were four different calculators for Male 3 and 7 site, and Female 3 and 7 site. Just not very practical and horrible design.

I decided to design a new calculator for the T-maggers. I emailed it to T-mag hoping they would hook me up with a little something for my efforts, but I never heard back. Anyway, no big deal, I’ve learned a ton from T-mag and you guys.

In my opinion, the calculator is pretty self-explanatory, but here is how to use it.

  • Select your sex.
  • Enter your age.
  • Enter your measurements (in mm), 3 per site. Each site MUST have all 3 fields completed.
  • For a 3-site calculation, complete the 3-site portion of the form.
  • For a 7-site calculation, complete the entire form.
  • Click on the Calculate button.
Here's the link:

Please post any bugs you find or any suggestions you have. FYI, this was tested with IE 6.0 and uses Javascript.

I hope you guys and girls find this to be useful.

Good design and accuracy. Thanks!

Thanks! Great design and easy to use! If only we could go back and make addendums to past articles.

Since I can’t make an addendum to my article, why don’t you make sure to send a letter to Reader Mail, so that it could be added as a semi-addendum.

So the link for the bodyfat calculator you provided in your article is no good? I tried this one, there was only a .6% difference…

Here’s a way to never screw up: Get a pair of digital calipers that do the calculations for you.

D Rock, nice job. Had to jump in here because I saw you go to Lehigh…what year are you? I went for a year before transferring. Keep up the good work.

No, the link in my article still works perfectly fine. D_rock’s new simple one site layout is a bit more user friendly - that’s the only advantage. Well, D_rock’s new calculator also uses the same equations to convert body density to %body fat. At the Rusty Iron Body Fat Calculator, they use a slightly different (yet, still valid) equation and that is why you got the 0.6% variation.

Both sites work perfectly fine, but just have different layouts and use a slightly different equation to convert body density to body fat percentage. Bottome line - pick one site and stick with it. I'd refer to D_rock's site only because it is exactly in line with my article using the Brozek equatin to cnnvert body density to %BF, whereas, the Rusty Iron BF Calc uses the Siri equation.

Yea, my suggestion rocks- lol.

Steve Coppola: I am a member of the elite Super Senior Club, a little too much partying my first couple of years.

Jason Norcross (and all): Would you like me to include the other calculation as well? If so, just point me in the direction of where I can find it.

I'm glad everyone seems to like it.

No, I don’t think you need both equations. If anyone wants them, I can easily provide them.

What I'd love to see is an additional menu on the t-mag site with this body comp calculator (and a link to my article on the calculator so people know where to pinch), a Massive Eating Calculator (JMB has one on his site) and other appropriate calculators that would help facilitate some of the practical applications in some of the T-Mag articles.

Well, looks like I've got something to send into Reader Mail.