Fitness Calculators
Free, science-backed tools to help you make informed decisions about your nutrition, training, and body composition goals.
Body Composition
Body Fat Percentage Calculator
Estimate your body fat percentage using the U.S. Navy Method with simple body measurements.
Lean Body Mass Calculator
Calculate your lean body mass (total weight minus fat) from your weight and body fat percentage.
Waist-to-Hip Ratio Calculator
Calculate your waist-to-hip ratio and see where you fall on WHO health risk categories.
Nutrition
TDEE Calculator
Calculate your Total Daily Energy Expenditure using the Mifflin-St Jeor equation to find how many calories you burn per day.
Macro Calculator
Calculate your ideal protein, carb, and fat intake based on your calorie target and fitness goal.
Calorie Deficit Calculator
Find out how many calories to eat per day to lose fat at a safe, sustainable rate.
Water Intake Calculator
Find out how much water you should drink daily based on your weight, activity level, and climate.
Protein Intake Calculator
Calculate your optimal daily protein intake based on your weight, activity level, and fitness goal.
Training
Frequently asked questions
Which calculator should I start with?
Start with the TDEE Calculator to find out how many calories you burn per day. This number is the foundation for setting calorie and macro targets. From there, use the Calorie Deficit Calculator if your goal is fat loss, or the Macro Calculator to dial in your protein, carb, and fat split.
How accurate are these calculators?
All calculators use peer-reviewed formulas and established methods (Mifflin-St Jeor for TDEE, U.S. Navy Method for body fat, etc.). However, every formula is an estimate. Individual variation in metabolism, body composition, and genetics means your actual numbers may differ by 5-10%. Use the results as a starting point and adjust based on real-world results over 2-3 weeks.
Do I need to sign up or pay to use these tools?
No. All calculators are completely free with no account required. There are no ads, no paywalls, and no data collection beyond standard analytics.
How often should I recalculate my numbers?
Recalculate every 4-6 weeks during an active fat loss or muscle-building phase, or whenever your weight changes by more than 5 lbs. Your calorie needs change as your body composition changes, so keeping your numbers current ensures continued progress.
Can I use these tools on my phone?
Yes, all calculators are fully responsive and work on any device: phone, tablet, or desktop. No app download is needed.