Free Fitness Calculators

8 science-backed tools to plan your training and nutrition. No signup required. Every calculator uses published formulas — the Mifflin-St Jeor equation for BMR and TDEE, the Epley formula for one rep max, the U.S. Navy circumference method for body fat, the Karvonen method for heart rate zones, and the Wilks coefficient for relative strength. Run your numbers here, then use them to set training loads, calorie targets, and cardio intensity.

All 8 calculators

• TDEE & Calorie Calculator
  Calculate your Total Daily Energy Expenditure and daily calorie target for your goal.
• One Rep Max Calculator
  Estimate your 1RM for any lift based on weight and reps performed.
• Body Fat Estimator
  Estimate your body fat percentage using the U.S. Navy method.
• Macro Calculator
  Get your ideal protein, carb, and fat targets based on your TDEE and goal.
• Heart Rate Zone Calculator
  Find your 5 training heart rate zones using the Karvonen method for smarter cardio.
• Power Output (FTP) Calculator
  Estimate your Functional Threshold Power and training zones for cycling or rowing.
• Wilks Score Calculator
  Compare your strength relative to body weight using the Wilks coefficient.
• BMI Calculator
  Calculate your Body Mass Index and see where you fall on the health spectrum.

Want a full plan based on these numbers?

FitForge applies Coach Voris's rules to build an adaptive workout and nutrition plan from your stats, then supports you with in-app guidance, progress tools, and reminders.

Get your custom plan →

Keep exploring

• Workout Library — free workouts by level & equipment
• Fitness Blog — science-backed training & nutrition
• Podcast — Deep-dive episodes