What your training actually says you can run.
Enter a recent race or hard effort and get your equivalent times for 5k, 10k, half marathon and marathon.
Useful for picking a goal time that is ambitious rather than imaginary.
Predictions are honest at distances near your effort and get optimistic as you extrapolate upwards — a marathon from a 5k is a hope, not a forecast.
How it works
Your effort is converted to a VDOT using Daniels' equations, then solved back to a time at each distance. Riegel's formula (T₂ = T₁ × (D₂/D₁)^1.06) is used as the sanity check near the anchor distance.
A 44:30 10k puts you around 1:38 for a half and 3:25 for a marathon — if you do the marathon-specific training. The prediction assumes you train for it.
Questions
How accurate are race predictions?
Honest near your anchor distance and increasingly optimistic as you extrapolate upwards. A marathon predicted from a 5k assumes marathon-specific training you may not have done.
Which effort should I enter?
The most recent one that was genuinely hard. A race is better than a training run.
Does it account for training?
This calculator does not. Inside Structur the prediction updates continuously from every hard effort you run.
This number is where Structur starts.
Coaches prescribe against it. Self-coached runners build a block around it. Either way it stays current on its own.