Running pace calculator
Both units at once, because training plans and race distances rarely agree on which one to use.
Pace, speed, and what a session actually means
Pace is time per unit distance and is how runners think; speed is distance per unit time and is what treadmills display. They are inverses, so a faster pace is a smaller number — the opposite direction from speed, which is a common source of confusion when moving between a watch and a treadmill.
The race projections apply your current pace to standard distances, which is useful for translating a training run into something familiar. They are not predictions: nobody holds their 5K pace for a marathon. Real prediction formulas account for the fact that sustainable pace drops as distance rises, and a marathon is typically run considerably slower per mile than a 5K by the same runner.
The cross-unit conversion is exact, using 1.609344 kilometres per mile rather than a rounded 1.6, which drifts by several seconds per mile at typical paces.
Questions
Can I predict my marathon time from a 5K?
Not directly from pace — the row above shows what holding this exact pace would give, which no one does. Endurance formulas that scale pace with distance give far more realistic estimates.
Why does my treadmill show a different number?
Treadmills usually display speed, not pace. Six miles per hour is a ten minute mile; the two move in opposite directions as you get faster.
What pace should I train at?
Most easy running should feel conversational, well slower than race pace. This calculator tells you what you did rather than what you should do.