Free fitness tools built for real people
FitCalc was created with a simple mission: make science-based fitness tools accessible to everyone, completely free of charge. Too many fitness websites are cluttered with ads, paywalls, or misleading information designed to sell supplements. We believe you deserve accurate, easy-to-use calculators that help you understand your body and train smarter.
From BMI to BMR, one-rep max to heart rate zones, our calculators cover the full spectrum of fitness metrics. Each tool is built using clinically validated formulas and tested for accuracy. We explain the science behind every calculation so you understand not just the number, but what it means.
Our articles are researched and written to give you the information you need to make smart training and nutrition decisions. No filler content, no clickbait — just practical, evidence-based guidance on everything from strength training fundamentals to advanced nutrition strategies.
Every tool and article on FitCalc is completely free. We don't charge subscriptions, hide features behind paywalls, or spam you with promotional emails. Our costs are covered by modest advertising that respects your experience.
Our calculators use the same formulas found in peer-reviewed research and clinical practice. BMR calculations use the Mifflin-St Jeor equation (the most accurate for modern populations). 1RM estimates use the Epley formula. Heart rate zones use the standard Karvonen method. We cite our sources and explain the limitations of each formula so you know exactly what you're getting.
No calculator is perfect. Body composition estimates like BMI and body fat percentage have known limitations — they can't distinguish between muscle and fat, and they don't account for bone density or frame size. Use these tools as guides, not definitive measurements. For precise body composition analysis, consult a healthcare professional.
Have a question, suggestion, or found an error? We'd love to hear from you. Visit our contact page to send us a message. We read every message and do our best to respond within 48 hours.