A Simple Body Fat Calculator

Here’s a simple body fat calculator for estimating body fat for men (the one for women is a bit more complicated). The formula, which we got from Gastelu & Hatfield’s Dynamic Nutrition for Maximum Performance, is as follows:

Take your morning waist measurement in inches (around the love handles, at the level of the navel).
Take your morning weight in pounds.
Calculate: (Total Body Weight x 1.082) + 94.420 = Weight Factor
Calculate: (Waist Measurement x 4.150) = Waist Factor
Weight Factor – Waist Factor = Lean Body Mass in Pounds
Total Body Weight – Lean Body Mass = Body Fat in Pounds
(Body Fat x 100) / Total Body Weight = Body Fat Percentage (BF%)
100 – BF% = Lean Body Mass Percentage

If you’d like to do a spreadsheet version we have one version set up especially for our Shape Up For Summer Contest, which you can download HERE. If you want to build your own, just set it up like this:

Column A:

  • Waist
  • Weight
  • Waist Factor
  • Weight Factor
  • LBM
  • Body Fat (lbs)
  • BF%
  • LBM%

Column B:

  • blank [input your waist measurement]
  • blank [input your weight]
  • =B1*4.15
  • =(B2*1.082)+94.42
  • =B4-B3
  • =B2-B5
  • =(B6*100)/B2
  • =100-B7

We know from using this and the Tanita scale at the gym that this method is accurate within about 4%. That’s a big sweep, so if you’re competitive you may want to be more accurate. For most guys tracking progress is the most important factor, so it’s possible to get by with a less accurate measurement and a mirror to see recordable results.


Image: Grant Cochrane / FreeDigitalPhotos.net