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FitCalcHub: Free Health & Fitness Calculators

Published October 26, 2026 3 min read

FitCalcHub by NOHAS · Free, simple health and fitness tools

Free Health & Fitness Calculators

Use these calculators to explore common health and fitness estimates: adult body mass index (BMI), basal metabolic rate (BMR), and approximate daily energy needs. Enter your details below to see an instant result without creating an account.

Important: These tools provide general estimates for adults aged 18 and over. They do not diagnose a condition or replace advice from a doctor, registered dietitian or pharmacist. Results can be less useful during pregnancy, for athletes with high muscle mass, and for people with certain medical conditions or a history of disordered eating. Do not use calorie estimates as a substitute for individual medical advice.

BMI Calculator

Calculate adult BMI from weight and height. BMI is a screening measure, not a direct measurement of body fat or overall health.

Common adult BMI screening ranges: below 18.5, underweight; 18.5–24.9, healthy-weight range; 25.0–29.9, overweight; 30 or above, obesity range. These ranges may not fit every individual.

BMR Calculator

Estimate basal metabolic rate (BMR), the approximate energy the body uses at rest, using the Mifflin–St Jeor equation.

The equation uses a binary sex-specific constant and may not represent every person. Activity multipliers are broad approximations, not measured energy expenditure.

Daily Calorie Calculator

Estimate your approximate daily energy needs. The tool multiplies your estimated BMR (Mifflin–St Jeor) by an activity factor to give a rough maintenance estimate, with an optional gentle adjustment.

Actual energy needs vary with health, medication, sleep, body composition, activity and other factors. A calculator cannot determine a medically appropriate intake for you.

How the calculators work

  • BMI: weight in kilograms divided by height in metres squared.
  • BMR: an estimate based on the Mifflin–St Jeor equation using age, height, weight and the selected equation option.
  • Daily energy: estimated BMR multiplied by an activity factor. This is a starting estimate, not a personalised nutrition plan.

When to seek personalised advice

Speak with a healthcare professional before making significant changes to diet or exercise if you are pregnant, have a chronic condition, take medicines that affect weight or appetite, are under 18, are older or frail, or have concerns about eating or body image. Seek urgent medical help for urgent symptoms rather than relying on a calculator.

Sources and further reading

Content review note: This page provides general educational information. It should be reviewed periodically against current public-health guidance.