Your Complete Fitness Calculator Hub
Explore powerful calculators for your body, nutrition, fitness, training, and supplement goals.
Discover our collection of free online health and fitness calculators designed to help you make smarter decisions about your body, nutrition, training and supplements. Calculate BMI, body fat, ideal weight, calories, macros, hydration, running pace, heart rate zones, VO₂ max, protein needs, creatine, caffeine, vitamins and more. Select a calculator below to get a quick, personalized estimate based on your information and fitness goals.
Weight & Body
Understand your body composition, weight and healthy body measurements.
BMI Calculator
Calculate your Body Mass Index and understand your weight category.
Body Fat Calculator
Estimate your body fat percentage and understand your body composition.
Ideal Weight Calculator
Estimate a healthy weight range based on your height and personal information.
Body Weight Planner
Plan your target body weight and monitor your progress toward your goal.
Weight Gain Calculator
Estimate calorie needs for gradual and sustainable weight gain.
Weight Loss Calculator
Estimate calorie targets that may support your weight loss goal.
Healthy Weight Range Calculator
Estimate a healthy body weight range using your height and standard references.
Body Surface Area Calculator
Calculate estimated body surface area from your height and weight.
FFMI Calculator
Estimate your Fat-Free Mass Index and lean muscularity.
Waist-to-Hip Ratio Calculator
Calculate your waist-to-hip ratio and understand its general health context.
Waist-to-Height Ratio Calculator
Compare your waist measurement with your height using a simple health indicator.
Lean Body Mass Calculator
Estimate lean body mass using your body measurements.
Calories & Nutrition
Calculate calories, macros, hydration and essential nutrition needs.
Calorie Calculator
Estimate your daily calorie needs based on your body and activity level.
Calorie Deficit Calculator
Estimate a calorie deficit that may support your weight loss goal.
TDEE Calculator
Estimate your total daily energy expenditure based on activity.
BMR Calculator
Estimate the calories your body uses at rest to support essential functions.
Macro Calculator
Estimate your daily protein, carbohydrate and fat targets.
Fiber Intake Calculator
Estimate your recommended daily fiber intake.
Omega-3 Intake Calculator
Estimate your daily omega-3 intake and nutritional target.
Nutrition Facts Calculator
Understand calories and key nutritional values in your food.
Meal Calorie Calculator
Estimate the calories in a meal and compare them with your daily target.
Sugar Intake Calculator
Estimate your recommended daily sugar intake and track consumption.
Water & Electrolyte Calculator
Estimate hydration and electrolyte needs based on activity and conditions.
Micronutrient Calculator
Explore estimated daily requirements for important vitamins and minerals.
Sodium Intake Calculator
Estimate a personalized daily sodium target based on activity, goals and climate.
Fitness & Training
Improve training performance, cardio fitness and exercise planning.
Running Pace Calculator
Calculate running pace, speed and estimated finish time.
Calories Burned Calculator
Estimate calories burned during exercise based on activity and duration.
Protein Calculator
Estimate daily protein needs based on body weight, activity and goals.
Water Intake Calculator
Estimate daily water needs based on weight, activity and lifestyle.
Heart Rate Zone Calculator
Estimate heart rate training zones for cardio and endurance workouts.
One Rep Max Calculator
Estimate your one-repetition maximum and training loads.
VO₂ Max Calculator
Estimate aerobic fitness and cardiovascular endurance.
Race Time Predictor
Predict estimated race finish times for common running distances.
Supplements
Explore supplement intake, dosage planning and nutrition support.
Creatine Calculator
Estimate creatine needs and explore common supplementation approaches.
Keto Calculator
Estimate calories and macronutrient targets for a ketogenic-style diet.
Supplement Cost Calculator
Estimate your daily, monthly and yearly supplement spending.
Supplement Intake Calculator
Organize supplement intake and estimate daily amounts.
Vitamin D Calculator
Explore estimated vitamin D needs based on personal information.
Caffeine Calculator
Estimate caffeine intake and compare it with commonly used daily limits.
Electrolyte Calculator
Estimate electrolyte needs to support hydration during activity.
Magnesium Intake Calculator
Estimate daily magnesium needs based on age, sex and lifestyle factors.
How to Choose the Right Health & Fitness Calculator
FitCalculatorAI brings together free online health and fitness calculators covering body composition, nutrition, training, hydration, and supplements. Choose a category below to find the calculator that matches your current goal and get a quick estimate based on your information.
Explore the Four Calculator Categories
Each category focuses on a different part of your health and fitness journey. Start with the area that best matches what you want to understand or improve.
Weight & Body
Explore BMI, body fat, ideal weight, healthy weight range, lean body mass, body surface area, waist measurements, and other body composition tools.
Calories & Nutrition
Calculate calories, BMR, TDEE, macros, protein, fiber, hydration, electrolytes, omega-3, sodium, sugar, micronutrients, and other nutrition targets.
Fitness & Training
Find tools for running pace, calories burned, heart rate zones, one-rep max, VO₂ max, race performance, protein needs, and other training goals.
Supplements
Explore calculators related to creatine, caffeine, magnesium, vitamin D, electrolytes, keto planning, supplement intake, and supplement costs.
How to Use FitCalculatorAI Calculators
Most calculators require only a few basic details. For the most useful estimate, enter information that accurately represents your current body measurements, activity level, training, or nutrition habits.
Ready to get started? Choose a calculator below and enter your information to receive a quick, personalized estimate for your goal.