8 free health & fitness calculators

    Health & fitness calculators
    the numbers behind your goals.

    Calories, body composition, training and hydration — every tool uses a standard, published formula (Mifflin-St Jeor, US Navy, Epley and more) so you get a reliable estimate. No signup, no paywall. These are planning estimates, not medical advice.

    Calories & metabolism

    Body composition

    Training & performance

    Wellness

    Standard formulas, shown openly

    Each calculator states the exact formula it uses and links the source. Calories come from the Mifflin-St Jeor equation, the most accurate everyday BMR formula in published reviews; body fat uses the US Navy circumference method; one-rep max averages the Epley and Brzycki formulas. Nothing is hidden behind a black box — you can see how every number is produced and reproduce it yourself.

    How the calculators work together

    Start with BMR and TDEE to find your calorie needs, then split those calories into protein, carbs and fat with the macro calculator. Track body composition with the body-fat and ideal-weight tools, program training with the one-rep-max and pace calculators, and cover the basics with water intake. Each page links to the related tools, so you can move from "how many calories" to "what should they be made of" in a couple of clicks.

    Estimates, not medical advice

    These tools apply population-average formulas to the figures you enter. Real metabolism, body composition and hydration needs vary with genetics, health and lifestyle, so treat every result as a well-founded starting point rather than a diagnosis. For medical or nutrition decisions, check with a doctor or registered dietitian.