💪Fitness Calculators - Calories Burned, One Rep Max & Macros
Training without numbers is training blind. Our fitness calculators give you evidence-based results for calories burned by activity, one rep max estimates, macro targets by goal, and aerobic capacity—so you can train with a plan and measure real progress.
Macro Calculator
Calculate your optimal macronutrient intake based on your fitness goal: weight loss, muscle gain, or maintenance.
Use Calculator →Calorie Burn Calculator
Calculate how many calories you burn during exercise based on activity and duration.
Use Calculator →One Rep Max Calculator
Estimate your one rep max (1RM) based on the weight you can lift for multiple reps.
Use Calculator →Body Composition Calculator
Calculate your body composition including body fat percentage and lean muscle mass.
Use Calculator →Pace Calculator
Calculate your running or cycling pace based on distance and time. Perfect for training log tracking.
Use Calculator →Water Intake Calculator
Calculate your daily water intake needs based on body weight and activity level.
Use Calculator →Plate Math Calculator
Calculate the total weight of your barbell with plates. Essential for gym workouts.
Use Calculator →VO2 Max Calculator
Estimate your VO2 max — a key measure of cardiovascular fitness. Uses the Rockport 1-Mile Walk Test formula, accessible without laboratory equipment.
Use Calculator →Calories Burned Running Calculator
Calculate how many calories you burn while running. Results depend on your body weight, distance, and pace — heavier runners and faster paces burn more calories.
Use Calculator →Swim Pace Calculator
Calculate your swimming pace per 100 yards/meters, total swim time, or target distance. Works for training, open water events, and triathlon planning.
Use Calculator →Cycling Power Calculator
Calculate your cycling power output and training zones based on Functional Threshold Power (FTP). Used by cyclists and triathletes to structure training.
Use Calculator →Sit and Reach Flexibility Calculator
Evaluate your flexibility using the sit-and-reach test. Compare your score to age and gender norms to assess hamstring and lower back flexibility.
Use Calculator →Running Pace Calculator
Whether you're targeting a PR or estimating your finish time, this calculator computes your pace per mile and per kilometer from any distance and time. It also uses the Riegel formula — the endurance community's gold standard — to predict your finish times for 5K, 10K, half marathon, and marathon based on a recent race result.
Use Calculator →Why Use Our Fitness Calculators Calculators?
Calorie burn estimates for exercise are notoriously imprecise—commercial gym equipment typically overstates burn by 20–30%. Our calculators use MET (Metabolic Equivalent of Task) values from the Compendium of Physical Activities, which provides the most comprehensive and peer-reviewed database of exercise energy costs available. The results still vary with individual fitness level and intensity, but they're far more accurate than equipment displays that don't account for your actual body weight.
One rep max (1RM) estimation is essential for structuring progressive overload. The Epley and Brzycki formulas—used by most coaches—let you estimate your maximum from a submaximal effort at any rep range from 1 to 10. This is safer than testing your true maximum repeatedly, especially for beginners, and our calculator shows results from multiple formulas so you can average them or pick the one that best matches your experience.
Pro Tips for Fitness Calculators Projects
- 1Use 1RM estimates to set training percentages: 80–85% for strength sets, 65–75% for hypertrophy, 50–65% for endurance.
- 2Calorie burn varies with fitness level—as you get fitter, the same activity burns fewer calories at the same pace.
- 3Protein target for muscle building: 0.7–1.0 grams per pound of bodyweight daily, distributed across 3–5 meals.
- 4TDEE calculators assume average activity levels—track your actual calories vs. weight change to calibrate your individual maintenance.
- 5VO2 max improvements are best achieved through a mix of zone 2 base training and weekly high-intensity interval sessions.
- 6Progressive overload means adding load, reps, or sets over time—without progression, adaptation plateaus within weeks.
- 7Rest periods matter: 2–3 minutes for strength sets, 60–90 seconds for hypertrophy, 30–45 seconds for metabolic conditioning.