About GainCalculator
Accurate, free fitness calculators — built for people who train seriously and want data-driven answers.
What is GainCalculator?
GainCalculator is a free collection of fitness and health calculators covering powerlifting, body composition, nutrition, and cardio. Every tool gives you an accurate, science-backed result in seconds — no account, no email, no subscription required.
We believe good information should be accessible to everyone. Whether you're a competitive powerlifter, a recreational runner chasing a 5K PR, or someone trying to understand their BMI and calorie needs — this site is built for you.
How our calculators work
Each calculator uses peer-reviewed formulas and established sports science equations. We show you which formula is being used (Epley, Brzycki, Mifflin-St Jeor, Wilks 2020, etc.) and explain the underlying assumptions so you understand where estimates can vary.
All calculations run locally in your browser. We never send your data to a server. No analytics tracking beyond standard page views, no selling of personal data.
A note on accuracy: Calculators provide estimates based on population averages. Individual physiology, genetics, training history, and health status all affect real-world results. Always consult a qualified professional before making significant changes to your training or diet.
Our tool categories
| Category | Tools Include |
|---|---|
| Powerlifting & Strength | One Rep Max, Bench Press, Wilks, DOTS, IPF Points, Powerlifting Total, Training Max (5/3/1), Progressive Overload, FFMI, Strength Level |
| Body Composition | BMI, Body Fat %, Lean Body Mass, Ideal Weight, Waist-to-Hip Ratio |
| Nutrition | TDEE, BMR, Macros, Calorie Deficit, Protein Intake, Water Intake |
| Cardio & Running | Running Pace, 5K Pace, Marathon Pace, Heart Rate Zones, VO₂ Max, Calories Burned Running |
| Health & Wellness | Sleep Calculator, Max Heart Rate, Hydration, Intermittent Fasting |
Contact us
Have a suggestion, found an error, or want to request a new calculator? Get in touch — we read every message.