🏃‍♀️ Stay Fit With AI

Free, professional fitness calculators that give you personalized health insights instantly. No signup required, no hidden fees - just science-based tools to help you reach your goals.
100% Free Forever
Science-Based Results
No Signup Required
Mobile Friendly
Start Your Journey 🚀

🧮 Fitness Calculators

Choose from our collection of professional-grade calculators, each designed to give you precise, personalized results for your fitness journey.
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TDEE Calculator

Find your Total Daily Energy Expenditure with precise calorie targets for weight loss, maintenance, or muscle gain.

  • Activity level adjustments
  • Goal-specific calorie targets
  • Macro breakdown included
Calculate TDEE
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Body Fat Calculator

Accurate body fat percentage using the Navy Method with visual charts and health assessments.

  • Navy Method accuracy
  • Visual body fat charts
  • Health risk assessments
Calculate Body Fat
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Macro Calculator

Get personalized macronutrient ratios for any diet style - from keto to vegan, Mediterranean to high-protein.

  • 9 different diet styles
  • Lean body mass calculations
  • Meal timing strategies
Calculate Macros
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Protein Calculator

Precision protein requirements based on your lean body mass, activity level, and specific goals.

  • Lean mass-based calculations
  • Activity & goal adjustments
  • Optimal timing strategies
Calculate Protein
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Water Intake Calculator

Smart hydration recommendations based on your work conditions, climate, activity level, and special circumstances.

  • Work condition adjustments
  • Climate considerations
  • Activity-based scaling
Calculate Water Needs
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Ideal Weight Calculator

Find your optimal weight range using multiple proven formulas with frame size and demographic adjustments.

  • 4 proven formulas combined
  • Frame size adjustments
  • Demographic considerations
Calculate Ideal Weight
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One Rep Max Calculator

Calculate your maximum lift potential with training percentages and strength level assessments for better programming.

  • 4 proven formulas
  • Training percentages
  • Strength level rankings
Calculate 1RM
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Calorie Burn Calculator

Calculate calories burned during any exercise or activity with MET values and body composition considerations.

  • Comprehensive exercise database
  • Body composition adjustments
  • MET value calculations
Calculate Calories
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Insulin Resistance Check

Dr. Ben Bikman's quick assessment method to evaluate your metabolic health and insulin sensitivity.

  • Dr. Bikman's methodology
  • Quick assessment tool
  • Metabolic health insights
Check Insulin Health

✨ Why Choose Stay Fit With AI?

We've built the most comprehensive, accurate, and user-friendly fitness calculators available anywhere - completely free.
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Precision Calculations

Our calculators use advanced formulas and body composition analysis for maximum accuracy, going beyond basic weight-based calculations.

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Always Free

No hidden fees, no premium tiers, no email required. All our tools are 100% free forever because we believe everyone deserves access to health tools.

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Mobile Optimized

Perfect experience on any device. All calculators are fully responsive and work seamlessly on phones, tablets, and desktops.

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Science-Based

Built on research from leading experts like Dr. Ben Bikman and Dr. Dominic D'Agostino, with proper medical disclaimers and evidence-based approaches.

Instant Results

Get your personalized recommendations immediately with detailed explanations and actionable next steps for your fitness journey.

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Beautiful Design

Clean, modern interface that's easy on the eyes and intuitive to use. Professional quality that exceeds expectations.

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