Lean Body Mass Calculator: How To Calculate Your Lean Body Mass

Akash Sehrawat

< 1 min read | Aug 2, 2017

In the picture below, where I am wearing a Red T-Shirt, I was ~ 175 lbs ( 79.5 kg) at 20% body fat percentage. What is my lean body mass?



Come on, take out your calculator and do this with me.


Step 1) Calculate Your Fat Mass


Fat Mass: 175 lbs x 20% = 35 lbs.


My Fat Mass was 35 lbs.


Fat Mass is simply the adipose tissue in my body. Subcutaneous fat (fat underneath my skin), Visceral fat (fat surrounding my organs like heart/liver etc) and intramuscular fat (fat surrounding the muscles).


Subcutaneous fat + Visceral Fat + Intramuscular Fat = 35 lbs ( 15.9kg)


Related Articles: 


Body Fat Percentage: 3 Ways To Measure It


Body Fat Percentage Chart For Men & Women (With Pictures)


Step 2) Lean Body Mass = Total Weight – Fat Mass


Lean Body Mass: 175 lbs – 35 lbs = 140 lbs.


My Lean Body Mass was 140 lbs. So what does Lean Body Mass comprise? Everything except for your fat mass.


What Does ‘Everything’ Comprise Of?


Water– 70% of your body is water.


Bone Mass– Your skeleton or bone weight


Organ weight- like heart, liver, stomach, kidneys etc


Skin Weight


Blood Weight


And anything else that is left except for Fat Mass


Here Is Your Homework


Shaily is 130 lbs at 29% Body Fat percentage. Calculate her Fat Mass. Calculate her Lean Body Mass. Let me know your answers below.


If you also have any comments, doubts or queries, let me know below!

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About Akash Sehrawat

Akash is a creator of 25+ programs and certificate courses in which more than 200,000 students have enrolled both on Udemy and Fabulous Body's native platform. Akash is also an author of three books that can be found on Amazon. His answers on Quora have gathered more than 12 million views in less than a year.


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Shama ismail
Shama ismail
3 years ago


Shaily is 130 lbs at 29% Body Fat percentage.

Calculate her Fat Mass.
130 lbs * 29% = 37.7 lbs (Fat mass) (17kg)

Calculate her Lean Body Mass.
Lean body mass = total weight(pounds) – fat mass
=130 – 37.7
=92.3 lbs (42 kg)