💪 Free Online Health Tools
Free online health & fitness calculators — TDEE, BMR, macros, one-rep max, heart rate zones, ovulation, pregnancy due date, and more. Private, instant, no signup.
17 tools available · 100% free · No signup required
TDEE Calculator
TDEE Calculator finds your Total Daily Energy Expenditure online for free. Get daily calorie needs by activity level using the Mifflin-St Jeor formula.
Protein Intake Calculator
Protein Intake Calculator finds your daily protein needs in grams online for free. Calculate protein based on body weight and your fitness goal.
One Rep Max Calculator
One Rep Max Calculator estimates your 1RM from weight and reps online for free. Uses the Epley formula and shows a full percentage training chart.
Heart Rate Zone Calculator
Heart Rate Zone Calculator finds your training zones from your age online for free. Calculate max heart rate and 5 target zones for cardio workouts.
Waist Hip Ratio Calculator
Waist Hip Ratio Calculator finds your WHR and health risk category online for free. Enter waist and hip measurements to assess body fat distribution.
Sleep Calculator
Sleep Calculator finds the best bedtime or wake-up time online for free. Uses 90-minute sleep cycles so you wake refreshed between cycles, not mid deep sleep.
Lean Body Mass Calculator
Lean Body Mass Calculator finds your fat-free mass online for free. Enter weight and body fat percentage to get lean mass and fat mass instantly.
Dog Age Calculator
Dog Age Calculator converts your dog's age to human years online for free. Uses the modern AVMA phased model with breed-size adjustment, not the old ×7 rule.
Pregnancy Due Date Calculator
Pregnancy Due Date Calculator estimates your baby's due date online for free. Enter your last period date to get your EDD and trimester milestones.
Ovulation Calculator
Ovulation Calculator finds your fertile window and ovulation day online for free. Enter your last period and cycle length to plan or track conception.
Menstrual Cycle Calculator
Menstrual Cycle Calculator predicts your next period dates online for free. Enter your last period and cycle length to see your next six period start dates.
Macro Calculator
Macro Calculator splits your daily calories into protein, fat, and carbs online for free. Get gram targets for your macros based on TDEE and body weight.
Pregnancy Weight Gain Calculator
Pregnancy Weight Gain Calculator finds your recommended weight gain range online for free. Based on pre-pregnancy BMI following IOM guidelines.
Pace to Speed Calculator
Pace to Speed Calculator converts running pace to speed online for free. Turn minutes per km or mile into km/h and mph, and back again, instantly.
Calories Burned Calculator
Calculate calories burned during exercise using METs, your body weight and duration. Pick an activity from the MET table for an instant, accurate estimate.
BAC Calculator
Estimate your Blood Alcohol Content using the Widmark formula from drinks, body weight, sex and time. An estimate only — never use it to decide whether to drive.
Steps to Calories Calculator
Convert your daily steps into calories burned and distance walked. Enter steps, weight and height for a personalised estimate. Free, instant and private.
Reaching a health or fitness goal is far easier when you can turn it into concrete numbers. These health and fitness calculators help you do exactly that: work out how many calories your body burns in a day, split those calories into protein, carbs, and fat, estimate the heaviest weight you can lift once, find your target heart-rate zones for training, or track a pregnancy timeline. Every calculation happens in your browser, so the personal details you enter — weight, age, cycle dates — never leave your device. Athletes tracking performance, people managing their weight, expectant parents planning appointments, and fitness enthusiasts designing workout programmes all use these tools to replace rough guesses with personalised figures.
Plan training and nutrition with real targets
The TDEE and BMR calculators give you a daily calorie baseline using established equations, and the macro calculator turns that number into practical gram targets for each meal. Lifters can estimate a one-rep max from a lighter set to program their sessions safely, while runners and cyclists can find the heart-rate zones that match easy, tempo, and threshold efforts. Rather than following generic advice, you get figures tuned to your own body and goals. The body-fat estimator helps you distinguish between weight that is muscle and weight that is fat, which matters far more than the number on the scale alone. Combine it with the BMR result to understand how body composition shifts your calorie needs over time.
Guidance for planning, not a medical diagnosis
The pregnancy, ovulation, and menstrual-cycle tools estimate dates from the information you provide and are useful for planning and awareness. These calculators rely on standard formulas and population averages, so they cannot account for every individual medical factor. Treat the results as a well-informed starting point and consult a doctor, dietitian, or qualified trainer before making significant changes to your health, training, or nutrition. The equations used — Mifflin-St Jeor for BMR, Epley for one-rep max, Karvonen for heart-rate zones — are cited in each tool so you can verify the methodology independently and discuss the numbers with a professional if needed.