Health toolkit
Health calculators for build a healthier routine.
Free online health and fitness calculators to help you make informed decisions about your health, nutrition, and fitness goals.
Popular health calculators
- BMI CalculatorCalculate your Body Mass Index and understand your weight categoryBody & weight
- Calorie CalculatorCalculate daily calorie needs (BMR & TDEE) using Mifflin-St JeorNutrition & energy
- TDEE CalculatorTotal daily energy expenditure and calorie targets by activity levelNutrition & energy
- Ovulation CalculatorEstimated ovulation date and fertile window from your cyclePregnancy & fertility
30 calculators
Body & weight
7- BMI CalculatorCalculate your Body Mass Index and understand your weight category
- Body Fat CalculatorEstimate body fat percentage with the US Navy tape-measure method
- Ideal Weight CalculatorFind your ideal weight using four clinical formulas (Devine, Hamwi, Robinson, Miller)
- Lean Body Mass CalculatorEstimate lean (fat-free) mass and fat mass (Boer formula)
- Waist-to-Height Ratio CalculatorWaist ÷ height health-risk ratio — a simple BMI alternative
- Waist-to-Hip Ratio CalculatorWHR and WHO cardiovascular risk classification for men and women
- BSA CalculatorBody surface area by Mosteller and Du Bois, with mg/m² dose math
Nutrition & energy
6- Calorie CalculatorCalculate daily calorie needs (BMR & TDEE) using Mifflin-St Jeor
- TDEE CalculatorTotal daily energy expenditure and calorie targets by activity level
- BMR CalculatorBasal metabolic rate (calories at rest) via Mifflin-St Jeor
- Macro CalculatorCalculate protein, carbs, and fat macros based on calories and diet style
- Protein CalculatorDaily protein target by body weight and goal, with per-meal breakdown
- Water Intake CalculatorCalculate daily water needs based on weight, activity, and climate
Fitness & training
6- Calories Burned CalculatorCalories burned for 25 activities using Compendium MET values
- Heart Rate Zone CalculatorFind your 5 heart rate training zones using max heart rate
- Target Heart Rate CalculatorFind your 5 training heart rate zones using the Karvonen method
- One-Rep Max Calculator1RM from any set (Epley & Brzycki) with 65-95% training loads
- Pace CalculatorSolve running pace, time, or distance with race-time projections
- VO2 Max CalculatorEstimate cardio fitness (VO₂ max) from resting heart rate
Health markers
6- Blood Pressure Category CheckerClassify a reading with AHA categories (normal to crisis)
- A1C CalculatorConvert A1C to estimated average glucose (eAG) and back
- Cholesterol Ratio CalculatorTotal:HDL ratio and non-HDL cholesterol heart-health markers
- Sleep Cycle CalculatorIdeal bedtimes and wake-up times on 90-minute sleep cycles
- BAC CalculatorEstimate blood alcohol content (Widmark) — an estimate, never for driving
- Alcohol Units CalculatorConvert drink volume and ABV into UK units and US standard drinks
Pregnancy & fertility
2Clinical & nursing
3Health calculator FAQ
- Can these health calculators diagnose a condition?
- No. Health calculators such as BMI, body fat, BMR, blood pressure category, and A1C are informational screens based on published formulas. They can't account for your full medical history. Talk to a doctor or other qualified clinician about any health concern.
- Which formulas do the health calculators use?
- Each calculator names its method on the page — for example Mifflin-St Jeor for BMR and TDEE, the US Navy method for body fat, the Widmark formula for blood alcohol, and the Karvonen method for heart rate zones — so you can see exactly how the estimate is made.
- Are the clinical calculators meant for professionals?
- Yes. The nursing dose, IV drip rate, BSA, and medical unit converter tools are study and decision-support aids for trained professionals and students. Every result must be independently verified against your facility's protocol before it is used.