AboutFitlydoo
At Fitlydoo, our mission is to make health and wellness information easier to understand through free, easy-to-use calculators and educational resources. We believe everyone should have access to reliable tools that help them make informed lifestyle decisions.
Why we exist
Our Mission
Fitlydoo exists to provide free online health calculators covering nutrition, hydration, metabolism, fitness, and overall wellness. We believe that understanding your own body should not require a personal trainer, a nutritionist, or an expensive app subscription.
Every tool we build is designed with simplicity at its core. You enter a few pieces of information about yourself, and we give you clear, meaningful results — along with plain-language explanations so you understand what the numbers actually mean.
Accessibility is equally important to us. Fitlydoo works across all devices, requires no account, and will always be completely free. Whether you are just starting a fitness journey or looking to fine-tune your nutrition, our calculators are here to help you better understand your personal health metrics.
Behind the numbers
How Our Calculators Work
Fitlydoo calculators use widely accepted formulas and established calculation methods to produce their estimates.
For example, our BMR and TDEE calculators are built on the Mifflin-St Jeor equation — the most widely validated formula for estimating resting calorie needs in the general population. Our protein and macro calculators draw on research-backed guidelines from sports nutrition and dietetics literature.
Where multiple approaches exist, we select the method most appropriate for general-population use and make the underlying logic transparent on every calculator page.
It is important to understand that all results are estimates. No online calculator can account for every individual variable — body composition, medical history, hormonal factors, and genetics all play a role. Our tools are designed to educate and guide, not to diagnose or treat any medical condition.
- Peer-reviewed formulas used wherever available
- Metric and imperial inputs supported on all calculators
- Results explained in plain language, not just raw numbers
- Educational content included alongside every calculator
- Regularly reviewed and updated as guidelines evolve
What we stand for
Our Values
Free to Use
Every calculator and resource on Fitlydoo is available at no cost — no sign-up, no subscription, no paywalls.
Easy to Understand
Results are presented with plain-language explanations so you always know what the numbers mean for your health.
Evidence-Based
Our calculations are based on recognised, peer-reviewed formulas used by health and fitness professionals worldwide.
Always Improving
We regularly add new calculators and expand our educational content library based on user needs and emerging research.
Our library
What You'll Find on Fitlydoo
We are building a comprehensive library of free health and wellness calculators, organised into categories that cover the full picture of personal health.
Nutrition Calculators
Protein, macros, calories, and daily nutrient targets.
Hydration Calculators
Daily water intake based on body weight, activity, and climate.
Metabolism Calculators
BMR and TDEE to understand how your body burns energy.
Fitness Calculators
Training-related tools to support performance and recovery.
Weight Management Calculators
Calorie targets for fat loss, maintenance, or muscle gain.
Body Measurement Calculators
BMI, body fat estimates, and other body composition tools.
Our calculator library is continually growing. New tools are added regularly based on user demand and emerging wellness research.
Important Disclaimer
Fitlydoo calculators provide estimates for educational purposes only. They are not a substitute for professional medical advice, diagnosis, or treatment. The results you receive are based on general population formulas and cannot account for individual health conditions, medical history, or clinical factors.
Always seek the advice of a qualified healthcare professional — such as a registered dietitian, physician, or certified fitness professional — with any questions you may have regarding a medical condition, dietary changes, or an exercise programme. Never disregard professional medical advice or delay seeking it because of something you have read or calculated on this website.
FAQ
Frequently Asked Questions
Yes. Every calculator and every piece of educational content on Fitlydoo is completely free. There is no subscription, no sign-up required, and no hidden cost. Our goal is to make reliable health information accessible to everyone.
Fitlydoo calculators use widely accepted, peer-reviewed formulas — such as the Mifflin-St Jeor equation for BMR/TDEE calculations and established hydration guidelines for water intake. Results are estimates based on the inputs you provide and are designed to be a helpful starting point, not a clinical measurement.
The results provide useful estimates for general health awareness and educational purposes. However, they are not a substitute for professional medical advice. Individual health conditions, medications, body composition, and other personal factors can significantly affect your actual needs. Always consult a qualified healthcare professional for personalised guidance.
Fitlydoo is designed for adults looking to better understand their nutrition, hydration, metabolism, and fitness metrics. It is especially useful for people tracking calorie intake, setting fitness goals, or simply wanting to learn more about how their body works. It is not intended for use by people with specific medical conditions without professional supervision.
Yes. We are actively building new calculators and expanding our educational library. Planned additions include body fat percentage calculators, one-rep max calculators, sleep calculators, and more. Our goal is to become the most comprehensive free health calculator resource available.
We welcome suggestions from our community. If there is a health or wellness calculator you would like to see on Fitlydoo, you can reach out via our newsletter or contact form. We review every suggestion and prioritise calculators that would benefit the most users.
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Explore the Health Calculators library
Browse our free collection of evidence-based nutrition, hydration, metabolism, and fitness calculators — all designed to help you understand your health better.
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