What this result means
Two clocks at two distances are hard to compare by eye. This tool estimates VDOT for each race and reports the higher index as the stronger endurance performance. Optionally, the same age is applied to both for WMA percent when the distances are supported.
It is not a judge of which race “counted” emotionally, and it is not a course-certified ranking. A downhill 5K will beat a honest hilly 10K on VDOT. Read the numbers with the course in mind.
A 20:00 5K versus a 46:20 10K: VDOT will usually prefer the 5K if the 10K is a weaker endurance day, or the reverse if the 10K is the better performance. A 19:30 5K versus a 20:00 5K is a PB question — use the PB tool.
Age grade only appears when both races are 5K, 10K, half, or marathon. A 8 km time trial will compare on VDOT only.
Calculation method
VDOT from each race using Daniels’ formulas. Higher VDOT wins. Age-grade percent uses the same WMA subset as the age-grading tools when the distance matches. Comparison category for WMA on this page uses the male table for both sides unless you interpret female factors on the dedicated age-grade tools.
Deterministic. Still two models, not a lab.
This page’s optional age-grade path uses one shared age. For a careful male/female split, grade each race on the age-grading calculator. Heat and hills are not modelled.
Frequently asked questions
How do you compare a 5K and a 10K?
By VDOT. The race with the higher Daniels index is treated as the stronger endurance performance.
Can I compare two 5Ks?
Yes, but the PB improvement calculator is clearer for the same distance: it shows seconds and percent.
Does a faster VDOT mean I should race that distance?
No. It only compares those two performances. Training, tactics, and the course still matter.