About Rulator
Rulator is an advanced natural-language running calculator for pace, speed, race predictions, VO2Max, heat, altitude, splits, and unit conversions. Type running calculations like a code editor and get instant results.
Features
Pace & Speed Calculator
Convert between pace (min/km, min/mi) and speed (km/h, mph). Calculate your running pace from time and distance, or find out how fast you need to run to hit a target time.
Race Time Predictor
Predict your race finish time for 5k, 10k, half marathon, and marathon using the Riegel formula. Enter your current pace or a recent race time to see predicted results across all distances.
VO2Max Estimator
Estimate your VO2Max using the Jack Daniels formula based on your race performance. Get age and gender-graded fitness classifications to benchmark your aerobic capacity.
Heat & Altitude Adjustment
Adjust your target pace for hot weather or high altitude conditions. Find out what pace you should aim for when running in temperatures above 15°C or at elevation.
Frequently Asked Questions
How do I calculate my running pace?
To calculate running pace, divide your total time by distance. For example, if you ran 5km in 25 minutes, your pace is 5:00/km. In Rulator, type 25mins 5k to get your pace instantly.
How do I predict my race time?
Race time prediction uses the Riegel formula: T2 = T1 × (D2/D1)^1.06. For example, a 20-minute 5k predicts a marathon time of approximately 3:05:40. Type 4:00/km predict marathon in Rulator to calculate this.
What is VO2Max and how is it calculated?
VO2Max is the maximum rate of oxygen consumption during exercise, measured in ml/kg/min. Rulator estimates VO2Max using the Jack Daniels formula based on your race performance. Type 21:00 5k vo2max to get your estimate.
How does heat affect running pace?
Heat slows runners down. Above 15°C (59°F), expect approximately 1.5 seconds per kilometer slower for each degree increase. Type 5:00/km at 30c to see your heat-adjusted pace.
How do I convert pace to speed?
To convert pace to speed, divide 60 by your pace in minutes per kilometer for km/h, or by pace in minutes per mile for mph. For example, 5:00/km = 12 km/h. Type 5:00/km to kmh in Rulator.