About NutriMath

What We Do

NutriMath is a collection of free health and fitness calculators built for people who want clear, evidence-based answers about their nutrition and body composition. Every tool on this site is designed to give you an accurate, transparent result — whether you're estimating your daily calorie needs, checking your body fat percentage, or planning a macro split.

We cover a wide range of health and fitness topics: BMR and TDEE estimation using multiple validated formulas, body composition metrics (BMI, body fat, lean mass), macro and calorie calculators for weight goals, hydration and micronutrient references, and more. Each calculator includes detailed educational content explaining the science, the formulas, and the practical takeaways.

Why We Built This

Most health calculators online give you a single number with no context. They don't explain which formula they used, what the limitations are, or how to interpret the result for your situation. We built NutriMath because we wanted tools that show their work — tools we'd actually trust for our own health and fitness decisions.

Every calculator on NutriMath runs entirely in your browser. Your weight, height, age, activity level, and every other number you enter stays on your device. Nothing is sent to a server, nothing is stored, and nothing is shared. There are no accounts, no sign-ups, and no data collection.

Our Methodology

NutriMath calculators use peer-reviewed formulas and published research from nutrition science and exercise physiology. We implement established equations — Mifflin-St Jeor, Harris-Benedict, Katch-McArdle, the US Navy body fat method, and others — and cite the original research behind each one. When multiple formulas exist for the same measurement, we explain the differences and help you choose the right one.

All math is implemented in tested, modular code — not embedded in page templates. This means every calculator that shares inputs (weight, height, age) produces consistent results. Our test suite validates formula correctness, boundary conditions, and cross-calculator consistency.

Editorial Standards

Content on NutriMath is written to inform, not to sell. We do not promote specific supplements, diet plans, or fitness products. Educational content alongside each calculator explains how the underlying science works, what the key variables are, and when a particular formula does or doesn't apply. We update content when new research changes best practices or when user feedback reveals a gap in our explanations.

Important Disclaimer

NutriMath provides educational tools and general information about health and fitness. We are not doctors, dietitians, or certified health professionals. Calculator results are estimates based on the inputs you provide and published formulas — individual results vary based on genetics, medical conditions, and other factors these tools cannot account for. Always consult a qualified healthcare professional before making changes to your diet or exercise routine. See our full terms & disclaimer for details.

Contact

Have a question, found a bug, or want to suggest a calculator? We'd love to hear from you. Visit our contact page to get in touch.