Lean Mass Calculator

Lean mass, which people also call fat free mass, is your total body weight minus the fat part. We calculate it using a standard scientific formula: when you subtract your fat percentage from your total weight, you get your lean mass. This includes your muscles, bones, organs, and water content.

Your lean mass depends on many factors like your gender, age, how much you train, and your genetics. If you exercise regularly and lift weights, having higher lean mass usually means you have more muscle, better metabolism, and a stronger body. When you are working on body recomposition, you can use your lean mass measurements to set realistic goals for gaining muscle or losing fat.

FFMI (Fat Free Mass Index) or Lean Mass Index is a measurement that adjusts your lean mass according to your height. It helps you compare your muscle mass relative to your body frame size. Generally, a higher FFMI means you have more muscle compared to your height.

Definitely yes. Knowing your lean mass helps you adjust your nutrition, especially your protein intake, and set clear targets for building muscle, losing fat, or changing your body composition. You can combine this information with a macro calculator to plan your diet more effectively.

Not exactly the same. Lean mass includes not just your muscles, but also your bones, organs, and body water. Muscle mass is just one part of your total lean mass, but knowing your overall lean mass gives you a complete picture of all the non fat tissues in your body.

This is an estimation tool that uses mathematical formulas. While it gives you a good approximation for fitness tracking, it is not a replacement for professional medical body composition tests like DEXA scans. Please use it for fitness planning and tracking purposes only, not for medical diagnosis.

For most people, checking your lean mass every 4 to 6 weeks is enough to track your progress properly. If you are actively trying to build muscle or lose fat, you might want to check every 2 to 3 weeks to see how your body is changing.

For men, a lean mass percentage between 70% to 90% is generally considered good, while for women, 60% to 85% is typical. These ranges can vary depending on your fitness level, age, and personal goals.

Yes, absolutely. With proper strength training and good nutrition, you can maintain and even increase your lean mass at any age. However, preserving muscle becomes more important as we get older, so paying attention to your lean mass is especially valuable as you age.

Yes, since lean mass includes your body water, how hydrated you are can affect the calculation. For the most accurate tracking, try to measure at similar times of day and when you have similar hydration levels.