About these fitness calculations
Running pace calculator takes your total time and distance and calculates your pace per kilometer and per mile, plus your speed in km/h and mph. Knowing your pace helps you run at the right effort level and set realistic race goals. A common beginner goal for a 5K is 30 minutes, which equals a 6:00 per kilometer pace.
Heart rate zones are calculated using the Karvonen method, which factors in your resting heart rate for a more personalized result than formulas that only use age. Zone 1 (50 to 60% of heart rate reserve) is light activity and recovery. Zone 2 (60 to 70%) is the aerobic fat-burning zone. Zone 3 (70 to 80%) is moderate cardio. Zone 4 (80 to 90%) is high intensity. Zone 5 (90 to 100%) is maximum effort and should only be sustained briefly.
Calories burned is estimated using the MET (Metabolic Equivalent of Task) formula. MET values represent the energy cost of an activity relative to rest. Walking slowly has a MET of about 2, while running fast has a MET around 11. The formula multiplies MET by your weight in kilograms and the duration to estimate calories burned.
Protein intake recommendations are based on your body weight and goal. General health maintenance requires about 0.8 grams per kilogram. Weight loss with muscle preservation needs around 1.2 grams. Muscle building typically calls for 1.6 grams, and high-level athletic performance may require up to 2.0 grams per kilogram per day.
One rep max (1RM) is calculated using the Epley formula: weight multiplied by one plus reps divided by 30. The result estimates the maximum weight you could lift for a single repetition. The calculator also shows recommended training weights at various percentages of your 1RM for different training goals.
Frequently asked questions
- What heart rate zone is best for fat loss?
- Zone 2 (60 to 70% of heart rate reserve) burns the highest proportion of calories from fat and can be sustained for longer periods. Higher zones burn more total calories per minute but rely more on carbohydrates. Both approaches work for fat loss when combined with appropriate nutrition.
- How accurate is the calorie burn estimate?
- MET-based estimates are reasonable averages but vary by individual. Body weight, fitness level, terrain, and exercise intensity all affect actual calorie burn. Fitness trackers with heart rate monitoring provide more personalized estimates but are still approximations.
- Should I train at my full 1RM regularly?
- No. Attempting your true one-rep max carries injury risk and should only be done occasionally with a spotter. Most strength programs use percentages of 1RM for training. For hypertrophy (muscle growth), 70 to 80% of 1RM for 8 to 12 repetitions is a common recommendation.