Aerodynamic Drag Calculator
Calculate aerodynamic drag force and power required to overcome air resistance. Input CdA, speed, and air density to estimate drag and power savings from position changes.
Free Endurance & Racing Calculators
16 toolsRunning, cycling, triathlon pacing, race prediction, and endurance nutrition calculators. Browse our free endurance & racing tools below — no sign-up required.
Age-Graded Running Time Calculator
Calculate your age-graded running performance percentage. Compare times across ages and genders using WMA/USATF age-grading standards.
Boston Marathon Qualifying Pace Calculator
Calculate your Boston Marathon qualifying time and target pace by age and gender. Includes BQ buffer recommendations and mile-by-mile pacing strategy.
Carb Loading Planner Calculator
Plan your carbohydrate loading protocol with daily carb targets based on body weight. Supports classic 3-day and modified 1-day carb loading strategies for endurance events.
Cycling Drafting Benefit Calculator
Estimate power savings from drafting behind another cyclist. Calculate drag reduction by wheel gap, group size, and position in the peloton.
Cycling FTP Test Calculator
Calculate your Functional Threshold Power (FTP) from 20-minute, 8-minute, or ramp test results. Get Coggan power training zones and W/kg classification.
Lactate Threshold Pace Calculator
Calculate your lactate threshold pace and heart rate training zones from recent race times. Estimate LT pace for 10K, half marathon, and marathon distances.
Power-to-Weight Ratio Calculator
Calculate your cycling power-to-weight ratio (W/kg) and see where you rank from Cat 5 to World Tour pro. Compare climbing ability and race category.
Race Predictor (Riegel) Calculator
Predict race times at any distance using the Riegel formula. Estimate 5K, 10K, half marathon, and marathon times from a single recent race result.
Running Economy Calculator
Calculate your running economy (RE) as oxygen cost per kilometer. Compare your efficiency to elite benchmarks and track improvements with VO2 and pace inputs.
Sports Drink Formulation Calculator
Design your own sports drink with optimal carbohydrate concentration, sodium content, and osmolality. Calculate DIY sports drink recipes for training and racing.
Taper Week Planner Calculator
Plan your pre-race taper with a day-by-day schedule. Reduce training volume 40-60% over 1-3 weeks while maintaining intensity for peak race-day performance.
Triathlon Pacing Calculator
Calculate per-discipline pacing targets from a total triathlon finish time goal. Break down swim, bike, and run paces for Sprint, Olympic, 70.3, and Ironman.
Triathlon Transition Calculator
Calculate total triathlon time including swim, bike, run, T1, and T2 transitions. Plan splits for Sprint, Olympic, 70.3, and Ironman distances.
Ultra Marathon Nutrition Calculator
Calculate calorie, carbohydrate, sodium, and fluid needs for ultra marathon races. Plan nutrition by distance, pace, body weight, and conditions.
VO2max Sport Benchmark Calculator
Compare your VO2max to sport-specific benchmarks by age, gender, and competition level. See your percentile ranking and performance classification for running, cycling, and more.