TOOLS
Tools
Enter your height, weight, activity level and more to calculate research-based metrics, with links to the studies and articles behind each formula.
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How much room is left?
FFMI Calculator
Enter your height, weight and body fat % to calculate lean mass and adjusted FFMI, with a research-based reference range for natural lifters.
InputHeightWeightBody fat %OutputFFMI1 supporting studyCalculate - 02
Know your limit — safely.
One-Rep Max Calculator
Estimate your one-rep max from a recent set using four formulas (Epley, Brzycki, Lombardi, O'Conner), with a %RM conversion table.
InputWeight liftedRepsOutputEst. 1RMReference infoCalculate - 03
Reverse-engineer your intake.
TDEE Calculator
Calculate your BMR and TDEE from sex, age, height, weight and activity level, with calorie ranges and a macro (PFC) breakdown for cutting, maintaining or bulking.
InputSexAgeHeightWeightActivity levelOutputTDEE1 supporting studyCalculate - 04
Distribution over dose.
Protein Intake Calculator
Estimate your daily protein target from body weight and goal (hypertrophy, maintaining muscle while cutting, or general health), with the source study and target population noted for each range.
InputWeightGoalOutputDaily target3 supporting studiesCalculate - 05
Body Fat Percentage Calculator (Navy Method)
Estimate body fat percentage from neck and waist tape measurements using the U.S. Navy method, with the typical margin of error and reference bands.
InputHeightNeckWaistOutputBody fat %1 supporting studyCalculate
EVIDENCE BASED
Evidence-based calculators
Every tool uses formulas and reference values grounded in peer-reviewed research. Each tool card links to the studies behind it.
Peer-reviewed research
Backed by credible academic studies
Direct links to studies
Jump from each tool to its source
Continuously updated
Reviewed as new evidence emerges