VDOT score, training zones, race predictions for 8 distances, split tables and nutrition planner for running and triathlon
This running pace calculator combines everything a runner and triathlete needs in one tool: pace and speed calculation, a VDOT fitness score based on Jack Daniels' Running Formula, five training pace zones, race predictions for 8 distances from 1 km to the marathon, a split table, and a race nutrition planner.
VDOT is the key metric in the Daniels system. It is calculated from your race result at any distance and represents your current aerobic fitness level. Based on your VDOT, the calculator determines five training zones: Easy running, Marathon pace, Threshold (lactate threshold), Interval (95-100% VO2max), and Repetition. Each zone targets specific physiological adaptations.
Race predictions are calculated using the Riegel formula: T2 = T1 × (D2/D1)1.06. Enter your result at one distance to get predictions for all others. The split table shows your per-km or per-mile splits with the option to choose between even pacing and a negative split strategy.
The nutrition calculator is based on ACSM and ISSN guidelines for recreational athletes. It estimates carbohydrates (30-90 g/hr), fluid (400-800 ml/hr), sodium, and caffeine based on your weight, intensity, and temperature, and provides specific product recommendations and a fueling timeline.
Enter 5 km and your finish time in the RUNNING section. The calculator uses the Riegel formula to predict your marathon and other race times. For example, a 25-minute 5K predicts roughly a 3:52 marathon.
VDOT is a running fitness metric from Jack Daniels' Running Formula. VDOT 30-35 is beginner, 40-45 intermediate, 50-55 advanced, and 60+ is elite level.
Five zones: Easy (65-79% VO2max for recovery), Marathon pace, Threshold (lactate threshold), Interval (95-100% VO2max), and Repetition (faster than VDOT pace). Each zone develops different physiological qualities.
Aim for 40-60g of carbs per hour, which is 2-3 gels per hour. For a 4-hour marathon, plan for 8-10 gels. Use the NUTRITION section for a personalized calculation.
A race strategy where the second half is run faster than the first (typically 1-3% faster). Considered optimal for marathons. The split table lets you toggle between even and negative split strategies.
400-800 ml per hour depending on temperature and body weight. In hot conditions (above 25°C/77°F), aim for up to 800 ml/h. Drink 150-200ml every 15-20 minutes.
In the TRIATHLON section, select Ironman 140.6, enter your swim pace (min/100m), bike speed (km/h), run pace (min/km), and transition times. The calculator shows total time and a breakdown by discipline.
Enter your weight, race duration, intensity, and temperature. The calculator estimates carbs, fluid, sodium, and caffeine based on ACSM/ISSN guidelines, and provides specific product recommendations and a fueling timeline.