Dr. Andy Galpin

So as a sample calculation, let's try this.

Let's say you are 5'10".

And weighed 100 kilos.

Now, I'm picking 100 kilos because it makes the math very easy.

And for many of you listening, you're going to appreciate the fact that I've made the math somewhat simple for you.

So if I were to be 100 kilos in weight and my body fat percentage was 25, that means 25 of those kilos are fat and 75 are nonfat.

As I said earlier, most people that are decently trained anyways, of their lean body mass, somewhere between 45% to 50% of that is actual skeletal muscle.

And so if we were to take that 75%, divide that by 2%,

assuming 50%, this would mean you probably have something like 37.5 kilograms of actual muscle in your body.

And again, 25 kilos of fat.

If you wanted to calculate your FFMI score from there, all you would have to do is go back to that lean body mass number.

So in kilograms, so in this case, 75.

and divide that by your height, so how tall you are, in meters squared.

So if you're 5 foot 10 inches tall, this is 70 inches, which would be about 1.778 meters.

So you take 1.778, square that, and then you take 75 and divide it by that number.

This would produce, in this particular case, an FFMI score of 23.7.

Pretty decent overall.

You can also intuit if you looked at somebody who's 5'10", they're 100 kilos and 25% body fat.

This is an individual with a lot of muscle mass.

And so this probably makes sense that they'd be on the upper end of that spectrum.