Medical disclaimer

Last updated: 21 July 2026

FitTools provides calculators and editorial content for general information and education only. Nothing on this site is medical advice, diagnosis or treatment, and nothing here creates a clinician–patient relationship.

Estimates, not measurements

Every result on this site is an estimate produced by a published formula. Formulas describe population averages; individual results routinely differ. We show error bands and limitations wherever the underlying research provides them, and we encourage you to read them.

Speak to a professional

Consult your GP or another qualified health professional before changing your diet, exercise, sleep or supplement regimen — especially if you are pregnant, under 18, have a medical condition, take medication, or have a history of disordered eating. Never disregard professional medical advice, or delay seeking it, because of something you read on this site.

Emergencies

If you think you have a medical emergency, call 999 (UK), 911 (US) or your local emergency number immediately. For urgent but non-emergency health concerns in the UK, contact NHS 111.