Free, science-backed calculators for BMI, calories, body fat and more — built to help you understand your body and reach your fitness goals faster.
Accurate, easy-to-use tools designed to give you instant answers about your body and nutrition.
Check your Body Mass Index instantly and see which health category you fall into.
Open Calculator →Find exactly how much protein you need daily for muscle gain, fat loss, or maintenance.
Open Calculator →Find out exactly how many calories you need daily to lose, maintain, or gain weight.
Open Calculator →Estimate your body fat percentage using the U.S. Navy method — just a tape measure needed.
Open Calculator →Get your perfect daily protein, carbs, and fat split based on your body and goals.
Open Calculator →Find out exactly how much water your body needs daily based on your weight and lifestyle.
Open Calculator →Discover your healthy weight range using 4 scientific formulas — not just one number.
Open Calculator →Find the exact calories your body burns daily — the master number for any diet plan.
Open Calculator →Set your goal weight and see exactly when you'll reach it — with a safe daily calorie plan.
Open Calculator →Find your Basal Metabolic Rate — the calories your body burns at complete rest.
Open Calculator →Find your 5 training zones — from fat burn to max effort — and train smarter.
Open Calculator →Estimate your max strength for any lift — plus your full training percentage chart.
Open Calculator →Simple tools you can trust — no clutter, no tracking of your personal data, just answers.
Every calculator is completely free. No subscriptions, no hidden charges, ever.
All calculations happen in your browser. Your health data never leaves your device.
Built on peer-reviewed formulas like Mifflin-St Jeor and WHO standards.
No waiting, no loading screens. Get your numbers the moment you hit calculate.
Fully responsive design — perfect on mobile, tablet, and desktop.
No accounts, no emails, no passwords. Just open a tool and start calculating.
We've made understanding your health as simple as possible.
Choose the tool that matches your goal — BMI, calories, body fat, and more.
Add basic info like height, weight, and age. Everything stays on your device.
See your results immediately with clear explanations and healthy ranges.
Quick answers to common questions about CalcFitly.
Yes, 100% free. No subscriptions, no hidden fees, no sign-ups — every tool is free forever.
No. Just open a calculator, enter your details, and get instant results. No account or email needed.
No. All calculations run entirely in your browser. Your weight, height, and other details never leave your device.
Our tools use established, peer-reviewed formulas such as the Mifflin-St Jeor equation and WHO BMI standards.
No. CalcFitly provides educational tools only. Always consult a qualified healthcare professional for medical decisions.
It takes less than 30 seconds to know your numbers.
Calculate Your BMI — Free