we'd love to know whether this calculator (click the link above) matches your real-life race times.
It's based on a well-established formula - what do you think?
My first reaction was that its predictions were too fast, but I think that was because
a) I have a bit more speed than endurance; and
b) my instinct was to try to predict times at the extreme ends of the distance spectrum (eg marathon time from 5K time)