Free Fitness and Health Calculators
Twenty free tools for protein, macros, body composition, calories, weight goals, water, creatine, sleep, and fitness age. Each page names its formula, explains the limits, and keeps every entry private in your browser.
Reviewed by Chris Pruitt, Certified ASFA Personal Trainer. Updated August 29, 2026.
Nutrition
3 toolsFind your daily protein target and see how far your current intake is from it.
Open calculator →NutritionFree Macro CalculatorEstimate daily calories, protein, carbs, and fat for cutting, maintaining, or gaining.
Open calculator →NutritionKeto Macro CalculatorSet a low carb ceiling and calculate protein, fat, and total calories for a keto style plan.
Open calculator →Body Composition
4 toolsEstimate fat free mass index, normalized FFMI, and rough muscle potential.
Open calculator →Body CompositionBody Fat Percentage CalculatorUse the U.S. Navy circumference equations to estimate body fat from a tape measure.
Open calculator →Body CompositionArmy Body Fat CalculatorCheck the current 2026 Army waist to height standard with the official cutoff.
Open calculator →Body CompositionWaist to Hip Ratio CalculatorCalculate waist to hip ratio and compare it with population risk bands for men and women.
Open calculator →Calories Burned
4 toolsEstimate calories for common training, sports, and daily activities with published MET values.
Open calculator →Calories BurnedTreadmill Calorie CalculatorCalculate treadmill calories with speed, grade, body weight, and the ACSM walking or running equation.
Open calculator →Calories BurnedSteps to Calories CalculatorTurn a step count into distance, walking time, and calories using your height and weight.
Open calculator →Calories BurnedCalories Burned Walking CalculatorEstimate walking calories from distance or time, pace, weight, and optional incline.
Open calculator →Weight Goals
3 toolsCompare Devine, Robinson, Miller, Hamwi, and the healthy BMI range side by side.
Open calculator →Weight GoalsWeight Loss Percentage CalculatorSee pounds lost, percentage lost, and progress toward the five and ten percent marks.
Open calculator →Weight GoalsGoal Weight Date CalculatorTurn a daily calorie deficit into a best case calendar date and weekly loss rate.
Open calculator →Water and Creatine
3 toolsEstimate daily fluid from weight, exercise time, climate, and current intake.
Open calculator →Water and CreatineCreatine CalculatorCalculate a loading dose, four daily loading portions, and a practical maintenance dose.
Open calculator →Water and CreatineHow Much Water Should I Drink on CreatineEstimate base fluid and add a modest practical adjustment for loading or maintenance.
Open calculator →Sleep and Age
3 toolsFind bedtimes or wake times from average sleep cycles and a 15 minute sleep onset estimate.
Open calculator →Sleep and AgeSleep Debt CalculatorAdd up two weeks of short nights and estimate a gradual repayment plan.
Open calculator →Sleep and AgeFitness Age CalculatorEstimate VO2 peak with the published HUNT model and compare it with measured age norms.
Open calculator →How these calculators work
Each tool uses the published method named on its page. Every result is an estimate. The pages explain normal error, show real sources, and state when medical or official assessment matters more. Nothing entered is stored, sent, or transmitted.