Scientific Health & Fitness Calculators
Accurate, ad-free health tools backed by peer-reviewed academic literature. Jump straight to any category or search our complete library below.
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Caloric & Daily Energy Expenditure
Calculate your metabolic rate, total energy expenditure, and calorie deficit targets.
Basal Metabolic Rate (BMR) Calculator
Calculate exact resting energy expenditure using Mifflin-St Jeor, Harris-Benedict, and Katch-McArdle equations.
Total Daily Energy (TDEE) Calculator
Determine your total daily caloric burn factoring in BMR, TEF, NEAT, and exercise activity thermogenesis.
Daily Calorie Intake Calculator
Calculate personalized daily calorie targets for sustainable fat loss, recomposition, or muscle gain.
Calories Burned Calculator
Calculate calories burned across 50+ activities including running, cycling, swimming, and gym workouts.
Macronutrient Nutrition Targets
Evidence-based protein, carbohydrate, and healthy fat distribution guidelines.
Recipe Calorie Counter & Macro Analyzer
Break down multi-ingredient homemade meals, casseroles, smoothies, and meal-prep batches into exact per-portion calories and macro splits.
Pregnancy Nutrition & Calorie Calculator
Calculate trimester energy surplus (+0, +340, +452 kcal), protein scaling, prenatal micronutrient RDAs (Choline, Folate, Iron, DHA), and weight gain curves.
Daily Micronutrient Calculator
Calculate personalized daily vitamin, mineral, and electrolyte targets with vegan bioavailability multipliers and whole-food smoothie blueprints.
Free Macro Calculator
Calculate customized daily protein, carb, fat gram splits and per-meal pacing for your fitness goals.
Macro Calculator for Women
Calculate female macro targets customized for menstrual cycle phases (follicular vs luteal), hormone balance, and safe fat floors.
Macro Calculator for Weight Loss
Calculate evidence-based cutting macros (15-25% deficit) with high protein safeguarding to shed fat while preserving lean muscle.
Protein Calculator
Calculate optimal daily protein intake for muscle hypertrophy, strength, and caloric deficit lean mass preservation.
Carbohydrate Calculator
Calculate daily carbohydrate requirements in grams and calories based on athletic training volume and intensity.
Fat Intake Calculator
Calculate daily healthy dietary fat targets and clinical breakdown of saturated fat, MUFAs, and Omega-3 PUFAs.
Body Composition & Anthropometrics
US Navy body fat formulas, natural muscular potential (FFMI), visceral adiposity, and lean mass indices.
US Navy Body Fat Calculator
Calculate body fat percentage, lean vs fat mass, and ACE categories using the military-grade US Navy tape method.
Fat-Free Mass Index (FFMI) Calculator
Determine your muscular development, height-normalized FFMI score, and maximum natural genetic muscle ceiling.
Waist-to-Height Ratio (WHtR) Calculator
Screen for visceral abdominal adiposity and cardiometabolic risk using the clinical 'Rule of Half'.
Body Mass Index (BMI) Calculator
Calculate your exact Body Mass Index, WHO weight classification, BMI Prime score, and healthy weight limits.
Lean Body Mass (LBM) Calculator
Calculate lean tissue mass vs fat mass using Boer, James, and Hume clinical formulas and body fat percentages.
Healthy Weight Calculator
Find your healthy weight spectrum based on WHO BMI ranges (18.5–24.9), Robinson, Miller, and Devine equations.
Body Type & Somatotype Calculator
Determine whether your morphology is Ectomorph, Mesomorph, or Endomorph with skeletal bone frame analysis.
Strength, Powerlifting & Resistance Kinetics
Submaximal 1RM fatigue kinetics, training percentage tables, and international powerlifting scores.
One-Rep Max (1RM) Calculator
Predict single-rep maximums safely from submaximal lifts, complete with 50%–95% percentage matrices and warm-up pyramids.
DOTS & Wilks Strength Calculator
Calculate bodyweight-normalized powerlifting strength scores for Squat, Bench Press, and Deadlift totals.
Step Count, Locomotion & Incline Kinetics
Convert steps, calculate active caloric burn, cadence velocities, treadmill inclines, and race finish times.
Treadmill Incline Calorie Calculator
Calculate calories burned on treadmill incline walking (including 12-3-30), vertical elevation gain, and flat-ground speed.
Race Time & Pace Predictor
Predict 5K, 10K, Half Marathon, and Full Marathon finish times and split paces from any recent race performance.
Steps to KM & Distance Calculator
Convert steps to km, meters, and miles with height-based stride estimation, activity gait modes, and live walking progress.
Steps to Calories Burned Calculator
Calculate gross and net caloric burn from steps, factoring in body weight, cadence intensity, and fat oxidation substrate splits.
Steps per Minute (SPM) to Speed Calculator
Convert cadence (SPM) into km/h, mph, and min/km pace with interactive live tap tempo and joint impact biomechanics.
Steps to Miles Calculator
Convert daily steps to miles with 1 Mile, 5K, 10K, Half Marathon, and Full Marathon step benchmarks and walking/running times.
Daily Step Goal & Longevity Calculator
Calculate your optimal daily step target and age-stratified all-cause mortality risk reduction with a 4-week progressive ramp plan.
Hydration, Fasting & Circadian Sleep Architecture
Daily fluid requirements, metabolic fasting timelines (ketosis & autophagy), and 90-minute sleep cycles.
Daily Water Intake & Hydration Calculator
Calculate total daily fluid requirements, sweat rate workout compensation, and an optimal hourly drinking schedule.
Intermittent Fasting & Autophagy Calculator
Track your fasting window, eating window, and observe your body's journey through blood sugar stabilization, ketosis, and autophagy.
Sleep Cycle & Circadian REM Calculator
Calculate optimal bedtimes and wake-up alarms based on 90-minute ultradian sleep cycles and 15-minute sleep latency.
Cardiovascular & Clinical Health
Heart rate training zones, renal filtration rates, and forensic blood alcohol clearance.
Target Heart Rate Calculator
Calculate age-predicted maximum heart rate and 5 ACSM exercise training zones with resting heart rate reserve.
Glomerular Filtration Rate (eGFR) Calculator
Estimate kidney filtration rate and KDIGO Chronic Kidney Disease (CKD) staging using official race-free equations.
Blood Alcohol Concentration (BAC) Calculator
Calculate blood alcohol levels, legal driving status, and time-to-sober countdown based on drinks consumed.
Frequently Asked Questions
Are all BunnyCal health and fitness calculators free?
Yes, 100% of our online health and fitness calculators are completely free to use without registration, paywalls, or limits. You can also sync your personalized targets directly into the free BunnyCal mobile app.
Are BunnyCal calculators based on peer-reviewed science?
Every single BunnyCal calculator is constructed strictly using validated, peer-reviewed scientific formulas (such as Mifflin-St Jeor, Tanaka, Morton et al., 2021 CKD-EPI, Widmark, Boer, and ACSM standards) with complete academic literature references cited on every page.
Can I use both Metric (kg/cm) and Imperial (lbs/in) units?
Yes! All 30+ calculators feature an instant unit toggle allowing seamless conversion between Metric (kg, cm, mg/dL) and Imperial (lbs, feet/inches, US standard units).
