Goal Forecasting
Target Weight Calculator
Calculate target body weight from current lean mass and desired body fat percentage. Formula: Target Weight = LBM / (1 - Target BF%). Assumes lean mass is held constant. Practical for setting body composition goals with your strategy.
System Units
Awaiting Calculator Inputs
Fill in the fields above and hit Calculate to generate your body composition targets.
Formula & Math
Estimates current lean mass, then divides it by one minus target body fat percentage.
How to Interpret
Target weight estimates assume lean mass is held constant, which may not happen exactly.
Plan Integration
Take these estimations back to the main Strategy Finder assessment, or save them in your tracking logs in the local dashboard.
Target Weight Model: Lean Mass Goals
Science & physiological analysis for strategy selection
Reviewed by Divy Yadav, CSCS
Last updated: June 27, 2026 · BodyCompOS Editorial Board
Setting a target weight based on generic charts or historical weights often leads to unrealistic goals. If you set a target weight that is too low, you may end up losing significant muscle mass to reach it. The BodyCompOS Target Weight Calculator uses a body composition model to estimate your goal weight. It calculates your current lean body mass and estimates your target weight based on your desired body fat percentage, assuming your lean mass is maintained.
1. How to Use & Apply This Target
Input your current weight, body fat percentage, and target body fat percentage. Review the resulting target weight estimate. Use this target weight to plan your timeline and calorie goals. If the calculator recommends a weight change of more than 10% of your body weight, divide your program into multiple phases.
2. Mathematical Assumptions & Formula Logic
This calculator uses the lean mass conservation formula: `Target Weight = Current Lean Mass / (1 - Target Body Fat% / 100)`. It assumes that you maintain all of your current lean body mass through resistance training and adequate protein intake during your weight change phase.
3. Step-by-Step Worked Mathematical Example
Frequently Asked Questions
Q:What happens if I lose muscle mass during my cut?
If you lose muscle mass (lean body mass) during a fat loss phase, your final body weight will need to be lower than estimated to reach your target body fat percentage. To avoid this, prioritize strength training, consume adequate protein, and keep your deficit moderate.
Q:Can my target weight be higher than my current weight?
Yes. If your target body fat is higher than your current body fat (e.g. you are very lean and want to gain weight), the calculator will project a target weight that is higher, helping you plan a controlled caloric surplus phase.
Related Strategy Tools
Lean Body Mass Calculator
Calculate Lean Body Mass (LBM) from body weight and body fat percentage. LBM = Weight × (1 - BF/100). Differentiates metabolic tissue from stored fat for body composition assessment, calorie targeting, and goal planning.
Goal Timeline Calculator
Forecast timeline to reach target body weight using compounding metabolic decay rather than linear projection. Accounts for metabolic adaptation with conservative weekly rates: 0.75% for fat loss, 0.2-0.4% for muscle gain. Generates non-linear projection curves for realistic planning.
Body Composition Calculator
Generate a comprehensive body composition snapshot integrating BMI, WHtR, lean mass, fat mass, and body fat percentage. A multi-dimensional assessment to inform training and nutrition strategy selection for fat loss or muscle gain.