Your VDOT score is a number representing your running fitness level, typically ranging from 30 (beginner) to 85+ (world-class elite). It's calculated by inputting a recent race time into the VDOT calculator. The calculator uses Dr. Daniels' extensive research on the relationship between race performance and physiological capacity. For example, a 20:00 5K race corresponds to approximately VDOT 50, while a 3:00 marathon corresponds to VDOT 52. The calculation accounts for the fact that performance at shorter distances tends to predict slightly higher VDOT scores than longer distances for the same runner, reflecting differences in specific endurance versus speed capabilities. The most accurate VDOT scores come from races between 1500 meters and the marathon distance.

While VO₂ max measures actual maximum oxygen consumption in a laboratory setting, VDOT estimates effective VO₂ max based on race performance. This distinction is crucial because two runners with identical VO₂ max values can have different race performances due to variations in running economy. VDOT accounts for this by reflecting how effectively you use oxygen, not just how much you consume. A runner with better economy will have a higher VDOT score than another with the same VO₂ max but poorer economy. This makes VDOT more practically useful for training, as it reflects actual performance capability rather than just physiological potential.

The VDOT calculator provides five essential training paces: Easy/Long Run pace (65-78% VO₂ max), Marathon pace (75-84% VO₂ max), Threshold/Tempo pace (83-88% VO₂ max), Interval pace (95-100% VO₂ max), and Repetition pace (105-110% VO₂ max). Each pace serves specific physiological purposes: Easy pace builds aerobic base without excessive fatigue, Marathon pace develops specific endurance, Threshold pace improves lactate clearance, Interval pace enhances VO₂ max, and Repetition pace improves running economy and speed. The calculator precisely determines these paces based on your VDOT score, ensuring each workout targets the correct physiological systems for optimal improvement.

Recalculation frequency depends on your training phase and progress. During base building, recalculate every 8-12 weeks after a benchmark race. During intense training cycles, recalculate every 4-6 weeks if you've raced. After a breakthrough performance, recalculate immediately. During injury recovery or off-season, maintain previous VDOT but adjust paces based on perceived effort. Important: Only use race performances for calculation—training times or time trials are less reliable. The VDOT system assumes race conditions with maximal effort. If you improve significantly at one distance, your VDOT may increase, adjusting all training paces upward for continued progression.

Yes, one of the VDOT calculator's most powerful features is its race equivalency predictions. By inputting your performance at any standard distance, it can predict equivalent performances at other distances with remarkable accuracy. For example, a VDOT 50 runner (20:00 5K) would predict approximately: 1600m - 5:42, 3200m - 12:04, 10K - 41:40, Half Marathon - 1:32:00, Marathon - 3:11:00. These predictions assume similar conditions, terrain, and training specificity. Predictions are most accurate between 1500m and marathon distances. For ultra distances or trail races, predictions become less reliable due to different physiological demands.