Disclaimer
Disclaimer
Every result on FitCalc is an estimate from a published formula — not medical advice, not a measurement of your body. Never go below 1,200 kcal/day (women) or 1,500 kcal/day (men) without medical supervision.
Results are estimates
A formula describes a population average, not you. The Mifflin-St Jeor equation predicts BMR within roughly 10% for most people and misses by more for the very lean, the very muscular, and older adults. MET values for calories burned are averages from the Compendium of Physical Activities — your speed, terrain and efficiency shift the real number. Epley and Brzycki 1RM estimates are most accurate from sets of 10 reps or fewer and assume good technique. Riegel race-time predictions assume equal fitness and similar course conditions. Treat every result as a starting point, track the real trend for 2–3 weeks, and adjust from what actually happens.
Not medical advice
FitCalc is a general fitness and nutrition reference, not medical, dietetic or coaching advice. We are not doctors, dietitians or coaches, and we claim no credentials. Nothing on this site should be treated as a substitute for professional advice — especially if you have a medical condition, are pregnant, are under 18, have a history of disordered eating, or take medication that affects weight, appetite or heart rate. Consult a healthcare professional before starting a diet, a training programme, or a very-low-calorie intake.
Safety floors
Minimum safe intakes are 1,200 kcal/day for women and 1,500 kcal/day for men. FitCalc tools never recommend a target below these floors, and no target on this site should be followed below them without medical supervision. A very-low-calorie diet carries real risks — gallstones, muscle loss, hormonal disruption and cardiac problems — and is a medical intervention, not a do-it-yourself plan.
Exercise safety
Never attempt a true one-rep max without a spotter, a safe setup and proper warm-up — the 1RM tools exist precisely so you do not have to. Stop training and seek medical attention for chest pain, fainting, unusual breathlessness or joint pain that does not ease. Heart-rate zone estimates use the 220 − age or Tanaka formulas, which carry a typical error of ±10–12 bpm — perceived effort matters as much as the number.
Formulas and sources
The formulas used on this site are published and named on every page: Mifflin-St Jeor (1990) for BMR and TDEE, Epley (1985) and Brzycki (1993) for one-rep-max, Riegel (1977) for race-time prediction, the Compendium of Physical Activities for MET values, and the 1.6–2.2 g/kg evidence range for protein. We show the formula so you can check the maths — but showing a formula is not the same as proving it fits you.
Liability
FitCalc is provided “as is”, without warranties of any kind. We are not liable for any loss, injury or damage arising from the use of this site or reliance on its results. If a number looks wrong, tell us on the Contact page — we would rather fix a page than defend it.