Fitness Calculators
Level up your training with our free fitness calculators. Estimate your one-rep max, find your heart rate zones, calculate calories burned, and track your VO2 max — all backed by exercise science research.
1RM Calculator
Calculate your one rep max for any lift using the Epley, Brzycki, or Lombardi formulas. Get accurate strength estimates from your working sets.
Running Pace Calculator
Calculate your running pace, finish time, or distance for any race. Supports 5K, 10K, half marathon, and marathon with split predictions.
Calories Burned Calculator
Calculate calories burned during 100+ exercises including running, walking, cycling, swimming, and strength training. Based on MET values.
Steps to Calories
Convert your daily step count into calories burned. Factor in your weight, pace, and terrain for an accurate walking calorie burn estimate.
Rest Day Calculator
Calculate how many rest days you need per week based on training intensity, volume, experience, and sleep quality. Prevent overtraining now.
Heart Rate Zones
Calculate your five heart rate training zones based on max heart rate or the Karvonen formula. Optimize fat burn, endurance, and performance.
VO2 Max Calculator
Estimate your VO2 max using the Cooper test, Rockport walk test, or running performance. See your cardiorespiratory fitness level and percentile.
Lean Body Mass Calculator
Calculate your lean body mass (fat-free mass) using the Boer formula. Essential for setting protein targets and tracking body recomposition.
Our fitness calculators are built on validated exercise science formulas from the American College of Sports Medicine and peer-reviewed research. Calculate your one-rep max using the Epley formula, find your running pace for race predictions, discover your heart rate training zones with the Karvonen method, estimate your VO2 max without a lab test, and track calories burned using MET values from the Compendium of Physical Activities. All tools are reviewed by James Okafor, ACSM-CPT, CSCS.