How it works
Pace = time ÷ distance, time = pace × distance, and distance = time ÷ pace. Pace per mile is pace per kilometre × 1.60934. Race splits assume you hold the same pace for the whole distance — in practice most runners slow over longer races.
Frequently asked questions
Why do my race splits look optimistic?
Because they assume a constant pace. Use a race-time predictor adjustment, or pace the first half conservatively, for longer races.
Can I enter time as minutes and seconds?
Enter it as decimal minutes here: 27 minutes 30 seconds is 27.5 minutes.
Does this account for hills or heat?
No. Hills, heat, wind and fatigue all slow you down versus a flat, cool-weather calculation.