Fitness Calculators & Tools
93+ science-backed calculators to optimize every aspect of your fitness journey. All free, all private, all accurate.
Browse by Category
Body Measurement & Proportion
Assess your body proportions, track measurements, and compare against scientifically established ideals.
Strength & Lifting Performance
Calculate your one-rep max, plan barbell loading, and structure your strength training programs.
Calories Burned
Estimate calories burned from walking and cardio sessions, and turn steps, distance, and calorie targets into easy-to-log activity references.
Workout Programming & Optimization
Optimize your workout variables including volume, intensity, recovery, warm-ups, and training intervals.
Fitness Assessment
Evaluate your aerobic endurance, muscular performance, and overall physical fitness with standardized tests.
Nutrition & Logging
Track macronutrients, plan calorie intake, and log nutrition data with conversion tools and goal-based calculators.
Conversion & Reference
Quickly convert between unit systems, translate barbell and dumbbell loads, and reference competition standards for powerlifting and Olympic weightlifting.
All Tools
Casey Butt Muscular Potential Calculator
Estimate your natural muscular potential using Casey Butt's nonlinear frame-based model. Calculate max lean body mass, bodyweight, and muscular measurements from height, wrist, and ankle size.
Hypertrophy Volume Landmarks Planner
Plan and monitor weekly training volume per muscle group using MEV, MAV, and MRV landmarks. Build workouts day-by-day with an exercise database, track direct and indirect sets, and plan progression and deload weeks.
Breath Count Calculator
Count your breaths per minute with a tap timer or manual entry. Classify your respiratory rate against population norms for rest and exercise.
Breath Hold Test Calculator — CO2 Tolerance
Test your CO2 tolerance with the breath hold assessment. Built-in stopwatch, classification against population norms, and breathing improvement tips.
Breathing Pattern Awareness Calculator
Analyze your breathing pattern with minute ventilation, alveolar ventilation, dead space calculations, and efficiency analysis.
Elderly Mobility Scale (EMS) Calculator
Assess functional mobility with the validated 7-item Elderly Mobility Scale. Score key daily movements and track mobility level over time.
Fasting Progress Tracker
Log your fasting days, track weight trends, monitor streaks, and review adherence over time. All data stored locally in your browser.
Fitness Age Calculator
Estimate your fitness age from resting heart rate, waist measurement, and activity level using the NTNU/CERG non-exercise VO2max model.
Sit-Ups Test Calculator
Evaluate abdominal muscular endurance with the standardized 1-minute sit-up test. Compare results against age and sex normative data.
Vegan Protein Calculator
Calculate daily plant-based protein needs with PDCAAS/DIAAS digestibility adjustment, per-meal targets, lysine requirements, and complementary protein pairing guide.
Water Fasting Weight Loss Calculator
Estimate daily weight change during a water-only fast with fat vs water breakdown, metabolic phase tracking, and post-refeed projection.
Weight Converter
Convert between kilograms, pounds, stone, ounces, and grams. Includes quick-reference table and barbell plate conversions.
Bike Size Calculator
Find your ideal bike frame size from height and inseam for road, mountain, gravel, hybrid, and TT bikes with fit preference adjustment.
Bike Tire Pressure Calculator
Calculate optimal front and rear tire pressure based on rider weight, tire width, bike type, tire setup, and surface conditions.
Calories to Steps Calculator
Convert a calorie target into walking or jogging steps using MET-based formulas. See how many steps to burn off meals with a food reference panel.
Cycling CdA Calculator
Estimate your cycling CdA from body dimensions and riding position, or back-calculate from power and speed data. Compare positions and see watt savings.
Cycling Race Predictor
Predict cycling race finish time from power output, weight, distance, elevation, and aerodynamic parameters. Includes pacing and what-if scenarios.
Cycling Rolling Resistance Calculator
Calculate rolling resistance force and watt cost from Crr, total weight, speed, and surface type. Compare tire options and see power impact.
Cycling Watts Calculator — CP & W'
Calculate Critical Power and W' (anaerobic work capacity) from 2–3 maximal time trial efforts using the 2-parameter power-duration model.
Erg-to-Boat Speed Calculator
Predict on-water boat speed from your ergometer 2K time. Weight-adjusted predictions for all boat classes (1x through 8+) with condition modifiers.
Erg-to-Run Equivalence Calculator
Convert rowing ergometer performance to equivalent running paces and race times. VO2max-based predictions and distance ratio conversion for cross-training.
NP & IF Estimator
Estimate Normalized Power from average power using ride profile presets. Calculate Intensity Factor and Training Stress Score for cycling rides.
Rowing Critical Power Calculator
Calculate rowing Critical Power (CP) and W' from 2-3 maximal erg efforts. Estimate FTP, get time-to-exhaustion predictions, and plan race pacing.
Rowing FTP Calculator
Estimate rowing Functional Threshold Power from a 20-min test, 2K erg score, or Critical Power. Get 6 structured training zones with watts and split targets.
Rowing Race Pace Calculator
Plan your rowing race pace with 500m-by-500m split targets. Choose even, negative, or controlled-start pacing strategies with power and stroke rate guidance.
Rowing Stroke Efficiency Calculator
Analyze rowing technique with Distance Per Stroke (DPS) and Stroke Power Index (SPI). Compare to elite benchmarks and get drill targets for improvement.
Saddle Height Calculator
Calculate optimal bike saddle height using three proven methods: Hamley (109%), LeMond (88.3%), and Heel (106.5%). Includes crank length adjustment.
5:2 & 4:3 Calorie Cycling Calculator
Plan your weekly calorie cycling schedule with the 5:2 or 4:3 protocol. Normal and restricted day calories, macro breakdowns, and a visual 7-day schedule.
Cycling RPE Calculator
Map cycling perceived exertion (RPE 1-10) to power zones, heart rate zones, and session training load using the Borg CR-10 scale.
Marathon Pace Calculator
Generate per-km and per-mile split tables with even, negative, or positive split strategies for marathon, half marathon, 10K, and 5K races.
RIR to RPE Calculator
Convert between Reps in Reserve and RPE scales, estimate %1RM from set data, and get suggested working weights based on your one-rep max.
RPE Load Calculator
Log weekly sessions and calculate total training load, monotony, and strain using the Foster session-RPE method with visual load distribution.
Running RPE Calculator
Map running perceived exertion (RPE 1-10) to training zones, heart rate ranges, and session training load using the Borg CR-10 scale.
Running Split Calculator
Generate per-km, per-mile, per-400m, or per-200m split tables for any distance from 200m track sprints to full marathon.
Bicep-to-Thigh Circumference Ratio Calculator
Compare upper and lower body proportionality with the 2:3 bodybuilding standard and bilateral symmetry analysis for left vs right balance.
Daily Steps Activity Level Classifier
Classify your daily step count into activity level tiers (sedentary to highly active) based on Tudor-Locke et al. research with distance and calorie estimation.
Multi-Sport Calorie Calculator
Estimate calories burned from 50+ sports across 8 categories using 2024 Compendium MET values with recreational, competitive, and vigorous intensity levels.
Muscle-to-Fat Ratio Calculator
Calculate your lean mass to fat mass ratio with InBody-style body shape classification (C-shape, I-shape, D-shape) and population reference ranges.
NEAT Calculator — Non-Exercise Activity Thermogenesis
Estimate daily calories from non-exercise activities with a granular breakdown by occupation, household, transport, leisure, and postural activity.
Scuba Diving Calorie Calculator
Estimate calories burned during scuba diving and snorkeling using 2024 Compendium MET values with water temperature and current adjustments.
Sled Push & Pull Calorie Calculator
Estimate calories burned from sled push, pull, and drag exercises using load-to-bodyweight ratio intensity tiers and surface friction adjustments.
Volume-to-Intensity Ratio Calculator
Analyze training sessions for total volume (tonnage), average intensity (%1RM), Prilepin zone classification, and session type identification.
Zig-Zag Calorie Calculator
Create a calorie cycling plan with high, medium, and low calorie days using Mifflin-St Jeor BMR. Aligns with your training schedule for weekly calorie budgets.
Caffeine Intake Calculator
Track daily caffeine intake from 20+ sources. See mg/kg ratio, compare to the 400 mg reference, and get personalized pre-workout dose ranges based on ISSN research.
Dynamic Strength Index (DSI) Calculator
Calculate the Dynamic Strength Index ratio from ballistic and isometric peak force. Get training emphasis classification and sport-specific benchmarks.
Jackson-Pollock 4-Site Skinfold Calculator
Estimate body fat percentage using the Jackson-Pollock 4-site skinfold method (1985). Uses tricep, suprailiac, abdomen, and thigh — same sites for both sexes.
StairMaster Calories Burned Calculator
Calculate StairMaster calories burned by machine level (1-20), body weight, and duration. Includes step counts, handrail impact, and intensity zone classification.
Tai Chi Calories Burned Calculator
Estimate calories burned during tai chi by style (Yang, Chen, Seated, General) using MET values from the 2024 Compendium of Physical Activities.
AFT Calculator — Army Fitness Test
Score all 5 Army Fitness Test events (MDL, HRP, SDC, PLK, 2MR) with General and Combat MOS standards by age and sex.
Air Force PFA Calculator
Score the Air Force Physical Fitness Assessment across 4 components: Cardio (50pts), Body Comp/WHtR (20pts), Strength (15pts), Core (15pts).
Army Body Fat Calculator
Estimate body fat percentage using the AR 600-9 one-site tape test formula. Pass/fail against Army standards by age and sex.
Food Points Calculator
Convert food nutrition into a simplified point score using a generic public-domain formula. Includes meal logger, daily budget guide, and 25-food reference.
Magic Mile Calculator
Predict your race paces for 5K, 10K, half marathon, and marathon from a 1-mile time trial using Jeff Galloway's empirical multiplier formulas.
Sodium in Salt Calculator
Convert between salt and sodium using the NaCl 40% formula. Compare against WHO, AHA, and DGA daily limits with a 20-food sodium reference.
Cadence & Stride Calculator
Explore the speed-cadence-stride triangle. Input any two values to calculate the third, with what-if analysis, ground contact time estimation, and optimal cadence ranges.
Cycling Critical Power Calculator
Derive Critical Power (CP) and W' from 3–6 maximal efforts using linear regression. Get power-duration predictions, time-to-exhaustion estimates, and a 6-zone training system.
Kosmin Test Calculator
Predict 800m and 1500m race times from repeated 60-second maximal efforts using sex-specific Kosmin regression formulas. Includes protocol guide and distance equivalents.
Run-Walk Pace Calculator
Calculate your effective pace and finish time using the Galloway run-walk method. Set custom ratios, estimate calories, and use the Magic Mile test for race predictions.
Tinman Running Calculator
Estimate vVO₂max from a race result and get four Tinman training pace zones — Easy, Critical Velocity, Interval, and Repetition — with CV workout suggestions.
Treadmill Pace Calculator
Convert treadmill speed to running pace, calculate grade-adjusted outdoor equivalent (GAP), estimate elevation gain, and compare calorie burn between incline and flat running.
Physical Fitness Test Calculator
Comprehensive 5-domain fitness assessment: cardio, strength, endurance, flexibility, and body composition. Age/sex percentile scoring with composite fitness score.
Rest Time Between Sets Calculator
Get science-based rest period recommendations by training goal, exercise type, and intensity with PCr recovery tracking.
Calories to Kilograms Converter
Convert calories to body fat kilograms using the 7,700 kcal/kg estimate with deficit timelines and quick-reference table.
Bike Pace Calculator
Convert cycling speed to pace (min/km or min/mi) and estimate race finish times for popular distances including 40 km TT and century rides.
Weighted Calisthenics 1RM Calculator
Estimate your one-rep max for weighted pull-ups, dips, muscle-ups, and push-ups using bodyweight plus added weight with standard 1RM formulas.
Dumbbell to Barbell Converter
Convert dumbbell weight per hand to estimated barbell weight, adjusted for exercise type and experience level with practical rounding.
Kg to Lb Powerlifting Converter
Precise kg-to-lb and lb-to-kg converter for powerlifting with competition plate chart, IPF weight classes, and common weights reference.
Aerobic Stepper Calories Burned Calculator
Estimate calories from step aerobics by step height, intensity, and duration for personal journaling.
Jogging Calories Burned Calculator
Estimate jogging calories from duration, speed, terrain, and body weight for personal journaling. Designed for casual and recreational jogging.
Kilometers to Steps Calculator
Convert a kilometer target into a step goal using estimated or custom step length, with miles context included for journaling.
Miles to Steps Calculator
Convert a miles target into a step goal using estimated or custom step length, with kilometer context included for journaling.
Arm-to-Forearm Ratio Calculator
Track upper-arm and forearm proportions with a length-based brachial index mode and a circumference logging mode.
Smolov Jr Calculator
Generate a 3-week Smolov Jr schedule with configurable progression, rounded loads, and optional start dates for planning and journaling.
Ideal Shoulder Size Calculator
Calculate your ideal shoulder width using height-based, anatomical, and golden ratio formulas. Compare to population averages by age and gender.
Neck to Waist Ratio Calculator
Calculate your neck-to-waist ratio to understand upper body proportions. Compare to population averages and the classic tailoring 2x reference.
Waist to Height Ratio Calculator
Calculate your waist-to-height ratio (WHtR) — a simple body proportion metric. Compare to the commonly referenced 0.5 benchmark and population averages.
Push-Up Test Calculator
Evaluate your upper body push-up performance using standardized norms and scoring.
Shoulder to Hip Ratio Calculator
Calculate your shoulder-to-hip ratio to evaluate your body frame and proportional balance.
Chest to Waist Ratio Calculator
Calculate your chest-to-waist ratio to measure your upper body V-taper and aesthetic proportions.
Gym Workout Tracker
Track your gym workouts, log exercises, sets, reps, and weights with progress visualization.
Harvard Step Test Calculator
Evaluate your cardiovascular fitness using the Harvard Step Test with PFI score and VO2max estimation.
Height to Foot Size Calculator
Estimate foot size based on height, or compare your foot-to-height ratio against averages.
Ideal Forearm Size Calculator
Calculate your ideal forearm size using Steve Reeves, McCallum, height-based, and bicep-proportional formulas. Includes grip strength correlation, bicep-forearm balance meter, and population data by age.
Ideal Neck Size Calculator
Calculate your ideal neck size using Steve Reeves, McCallum, height-based, and head-based formulas. Includes metabolic syndrome risk screening, sleep apnea indicators, and population data by age.
Body Measurements Tracker
Track and monitor your body measurements over time with visual progress charts and trend analysis.
Japanese Interval Walking Calculator
Plan your Japanese interval walking sessions alternating between fast and slow walking intervals.
Physical Activity Calculator
Estimate calories burned and activity level based on your daily physical activities and exercises.
YMCA 3-Minute Step Test Calculator
Assess your cardiovascular fitness with the YMCA 3-Minute Step Test recovery heart rate method.
Waist to Chest Ratio Calculator
Calculate your waist-to-chest ratio to evaluate upper body proportions and V-taper shape.
Ideal Calf Size Calculator
Calculate your ideal calf size using Steve Reeves (Ankle × 1.92), McCallum, height-based, and symmetry formulas. Includes AWGS 2019 sarcopenia screening, population data, and ankle-based reference charts.
Tempo & TUT Calculator
Calculate time under tension from tempo notation, plan optimal tempos for your goals, and track total session TUT with three modes backed by research.
Average Torso Length Calculator
Calculate and compare your torso length against population averages based on height and gender.
Grecian Ideal Calculator
Compare your body measurements against the classical Greek ideal proportions for the aesthetically perfect physique.