Technical details about the calculations and formulas used in our Running Calculator. Understanding these methods can help you better interpret your results and improve your training.
Pace is calculated by dividing your total time by the distance covered. The result is expressed in time per unit distance (minutes per kilometer or mile).
Pace (min/km) = Total time (seconds) ÷ Distance (km) ÷ 60 Pace (min/mile) = Total time (seconds) ÷ Distance (miles) ÷ 60
The minutes and seconds components are separated for display purposes. For example, a pace of 5.5 minutes per kilometer would be displayed as 5:30 min/km.
Time is calculated by multiplying your pace by the distance. This helps you estimate how long it will take to complete a run at a given pace.
Time (seconds) = Pace (min/km) × Distance (km) × 60 Time (seconds) = Pace (min/mile) × Distance (miles) × 60
This calculation is useful for race planning and setting realistic goals. Enter your target pace and race distance to estimate your finish time.
Distance is calculated by dividing your total time by your pace. This tells you how far you can run in a given time at a specific pace.
Distance (km) = Total time (seconds) ÷ Pace (min/km) ÷ 60 Distance (miles) = Total time (seconds) ÷ Pace (min/mile) ÷ 60
This calculation is helpful for planning training runs when you have a fixed amount of time available and want to know how far you can go.
Age grading is a method developed by World Masters Athletics (WMA) to compare performances across different ages and genders. Our calculator uses the latest 2025 factors.
The system works by comparing your time to an age-adjusted world record equivalent, accounting for the natural decline in performance with age.
Age-Graded Percentage = (Age Standard / Your Time) × 100 Age-Graded Time = Your Time × (Open-Class Factor / Age Factor)
Race predictions estimate your potential times at standard race distances based on a completed performance. Our calculator uses multiple prediction models:
T2 = T1 × (D2/D1)^1.06 Where: T1 = time for your known performance D1 = distance of known performance T2 = predicted time for new distance D2 = new distance 1.06 = fatigue factor
T2 = T1 × (D2/D1)^1.07
These predictions assume similar conditions across distances. Most runners find they perform slightly better at their specialty distances compared to predictions.
This calculation compares your performance to the current world record at the closest standard distance.
Performance Percentage = (World Record Time / Your Time) × 100
Most recreational runners perform between 40-70% of world record level. Elite non-professional runners may reach 70-85%.
VO2max is a measure of the maximum amount of oxygen a person can utilize during intense exercise. It's considered one of the best indicators of cardiorespiratory fitness.
Step 1: Oxygen Cost = -4.6 + 0.182258 × V + 0.000104 × V² Step 2: %VO2max = 0.8 + 0.1894393 × e^(-0.012778 × t) + 0.2989558 × e^(-0.1932605 × t) Step 3: VDOT = Oxygen Cost ÷ %VO2max Where: V = speed in meters per minute t = time in minutes
Optimal training requires running at different intensities for different physiological adaptations. Our training pace calculator uses your estimated VO2max (based on Jack Daniels' VDOT system).
A balanced training program typically includes 70-80% of your running at easy pace.
Age grading allows you to compare your performances across different ages, accounting for the natural decline in athletic abilities as we age. It's particularly valuable for masters athletes (40+) to track performance over time.
Race predictions are most accurate when predicting similar distances (e.g., 5K to 10K) and when your training is balanced. They tend to be less accurate for very different distances.
Each formula uses different mathematical relationships between running performance and oxygen consumption. Daniels' formula is the most comprehensive as it accounts for race duration.
Use Easy/Long Run Pace for recovery days and long runs (60-120+ minutes). Use Threshold Pace for tempo runs. Use Interval Pace for VO2max intervals. Use Repetition Pace for speed work.