Aspiring Bodybuilders: Time to Ditch the Online Bodyfat Calculators

Updated June 11, 2020

Aspiring bodybuilders – it’s time to ditch the online bodyfat calculators and purchase a skin fold caliper. I know it’s easy just to click to a website, input your stats, and have a bodyfat percentage spit out. But that number is generally bunk.

To illustrate my point, I performed a random Google search for bodyfat calculator. I’m going to input the number of three vastly different individuals, and see what bodyfat percentage it spits out.

Subject A: Muscular and Overweight

Subject A is large. Maybe he’s a powerlifter who carries a ton of extra weight. Maybe he’s just some average schmoe who works a physically intensive job, and eats like a bear. Here are Subject A’s true stats…

Weight: 300 pounds
Height: 5?10?
Bodyfat Percentage: 40%
Lean Muscle Mass: 180 pounds
Fat Mass: 120 pounds

The two random websites I’ve found to check Subject A’s bodyfat levels are, and I didn’t have to dig for these sites; they were first page Google results for “bodyfat calculator.” Here are the results…… 17.6% Bodyfat

Health Central… 21.2% Bodyfat

There was no magic used here; no smoke and mirrors. I didn’t try to fool the calculators into skewing the results. I just plugged in Subject A’s numbers, and received the calculations.

Skin Fold Caliper

Subject B: Chunky and Muscular

Subject B isn’t too much different from Subject A. He is a strong, muscular lifter, but carries around quite a bit of excess fat. Maybe he’s a college kid with one too many keggers under his belt; maybe he’s a stocky football player. Here are Subject B’s true stats…

Weight: 220 pounds
Height: 5?10?
Bodyfat Percentage: 25%
Lean Muscle Mass: 165 pounds
Fat Mass: 55 pounds

And, here are Subject B’s results from the same 2 websites:… 16.8% Bodyfat

Health Central… 11.3% Bodyfat

Subject C: Twiggy

Subject C is a twig. He doesn’t have much muscle, but he doesn’t have a six pack either. He is underweight, but still obsesses about his six pack. So he takes prohormones and diets, or whatever the case may be. Here are Subject C’s stats…

Weight: 160 pounds
Height: 5?10?
Bodyfat Percentage: 15%
Lean Muscle Mass: 136 pounds
Fat Mass: 24 pounds

And, here are Subject C’s results from the same 2 websites:… 2.9% Bodyfat

Health Central… 3.8% Bodyfat


Generally online bodyfat calculators run too high or too low. As we’ve seen from our three test subject, neither of the websites used have been in the same universe as far as accuracy goes. You’re better off having your blind grandmother guess your bodyfat percenatge.

What’s the point?

The point is this: purchase a skinfold caliper. They aren’t expensive. Even the cheap models are far more accurate then some random online calculator.

I have been using Creative Health Products’ Slim Guide Skin Fold Caliper for two years running. It is far from being the best on the market, but it isn’t junk either. It is a usable, reliable, accurate, quality skin fold caliper. And, it comes with an instructional booklet that will help any caliper newb get on the stick quick.

Calipers provide millimeter readings of fat at various areas of the body. And though the numbers aren’t 100% perfect, they aren’t very far off. Let’s say you’re carrying exactly 60 millimeters of excess fat 2 inches to the right of your navel. A caliper may give you a reading of 55 mm or 63 mm. And if you take that same measurement three times a day and acquire an average, the accuracy of the reading will be even greater.

At most, using a caliper, your projected bodyfat level shouldn’t be more then a few percentage points off. This provides you with a consistent reading; a much truer directional heading.

And even though the percentage isn’t 100% perfect, the millimeter readings you’re taking don’t lie. If you have 20 mm of fat on your mid thigh, you have 20 mm of fat on your mid thigh. The caliper isn’t going to provide you with a 3 mm or a 40 mm reading. Again, it may be off by several millimeters, but for the cost, it is far more accurate then a website calculator.

It’s time to make the change. Invest $30, and stop guessing at your bodyfat percentage. Bodybuilding is a scientific endeavour. Stop flying blindly.

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