Free Health & Fitness Calculators

BMI, daily calories, and running pace — calculators that state their formulas and assumptions plainly. Informational only: nothing here is medical advice.

6 toolsFormula shown on every toolInformational only — not medical advice

BMI CalculatorBody mass index from height and weight, in US or metric units, with standard categories.Calorie / TDEE CalculatorDaily calorie needs (BMR and TDEE) via the Mifflin-St Jeor equation, with goal targets.Running Pace CalculatorPace per mile and kilometer from distance and time, with race presets and split times.Body Fat CalculatorBody fat percentage from tape measurements via the U.S. Navy circumference method, with category ranges.Water Intake CalculatorA daily drinking-water estimate from National Academies guidance, adjusted for exercise.Heart-Rate Zone CalculatorFive training zones by age, personalized with the Karvonen method when you know your resting pulse.

About these tools

The Health section brings Tallyloom's show-your-work approach to the most-searched fitness math: body mass index from height and weight, daily calorie needs using the Mifflin-St Jeor equation, and running pace with per-mile and per-kilometer splits.

Each calculator names the formula it uses and the assumptions behind it, because health numbers without context are easy to misread — BMI, for example, is a screening measure that doesn't distinguish muscle from fat.

These tools are informational only. They can't account for your medical history, and they are not a substitute for advice from a doctor, registered dietitian, or other qualified professional. Everything runs in your browser — your measurements are never uploaded.

These answer different questions and are easy to confuse. BMI and body fat percentage both estimate composition, but BMI needs only height and weight while the Navy tape method uses circumference measurements and separates muscle from fat far better — if BMI calls you overweight and you lift, the body fat tool is the more informative one. The Calorie / TDEE Calculator gives the daily energy figure to eat around; the Water Intake Calculator does the same for fluids, adjusted for exercise. Heart-Rate Zones and the Pace Calculator are for training rather than assessment: one tells you how hard to work, the other converts a target finish time into the per-mile pace that reaches it.

Guides

Heart-Rate Zones by Age: A Practical GuideAge-based training zones, the 220-minus-age estimate, the Karvonen method, and when medication or health history makes a generic chart unreliable.What BMI Does — and Doesn't — Tell YouWhere the BMI formula came from, what the standard categories mean, and the well-documented cases where the number misleads.All guides →

Frequently asked questions

Are these calculators medical advice?

No. They implement standard published formulas for general information. For decisions about your health, weight, or training, consult a qualified professional who knows your history.

Which calorie formula do you use?

The Mifflin-St Jeor equation, generally regarded as the most accurate of the common BMR formulas for the general population, multiplied by a standard activity factor to estimate total daily energy expenditure (TDEE).

Is my health data private?

Yes. Height, weight, and everything else you enter is processed entirely on your device and never sent anywhere.

Looking for something else? Try Converters · Education & Study or browse all tools.