Health Calculators

BMI, calories, macros, and body composition calculators.

BMI CalculatorCalculate Body Mass Index (BMI) from height and weight, in metric or imperial units, with weight category.Calorie CalculatorCalculate your daily calorie needs based on age, weight, height, activity level, and weight goal.BMR CalculatorCalculate your Basal Metabolic Rate (BMR) — the calories your body burns at complete rest.TDEE CalculatorCalculate your Total Daily Energy Expenditure (TDEE) based on BMR and activity level.Body Fat CalculatorEstimate body fat percentage using the U.S. Navy circumference method.Ideal Weight CalculatorEstimate ideal body weight using the Devine and Robinson formulas based on height and sex.Macro CalculatorCalculate daily protein, carb, and fat targets in grams based on your calorie goal and diet style.Protein CalculatorCalculate your recommended daily protein intake in grams based on body weight and fitness goal.Water Intake CalculatorEstimate your daily recommended water intake based on body weight, activity level, and climate.

Using health calculators responsibly

Health calculators are best used as screening and planning tools. BMI, calorie needs, body-fat estimates, hydration targets and similar outputs are estimates based on formulas or population reference values—not diagnoses.

Where possible, CalculatorAnything explains the formula, assumptions and limitations behind each result. For adults, BMI categories on this site follow the WHO and CDC adult thresholds; energy calculators use established predictive equations but can differ from measured metabolism; nutrition and hydration estimates require individual context.

Children and teens, pregnancy or breastfeeding, eating-disorder concerns, medical conditions, and medication-related needs often require different methods or professional guidance. If a result affects a health decision, discuss it with a qualified healthcare professional.

Good to know before you calculate

Energy calculators use the Mifflin-St Jeor equation, generally considered the most accurate predictive formula for adults, with standard activity multipliers from 1.2 to 1.9. Body-fat estimates use the US Navy circumference method.

Results are designed for adults. Children and teens, pregnancy, and many medical conditions need different methods, and the calculators reject values outside realistic adult ranges rather than returning a misleading number.

Use a result as a starting point and watch the trend over weeks rather than chasing a single number. If an estimate would change a medical or dietary decision, discuss it with a qualified professional.

Health calculator FAQs

Are these health calculators medical advice?

No. They are estimates based on published formulas and population thresholds, meant for screening and planning. Discuss results that affect a health decision with a qualified professional.

Can children or pregnant people use these calculators?

They are designed for adults. Children, teens and pregnancy need different methods, so the results here shouldn't be applied to them.

Why does the calculator reject some values?

Inputs outside realistic adult ranges (for example a height of 1.75 entered as centimetres) would give a misleading result, so the calculator explains what to check instead.