Pace and speed both describe how fast you're moving, but they measure it in opposite directions. Speed is distance per unit time (km/h or mph) — how many kilometres you cover in an hour. Pace is time per unit distance (min/km or min/mile) — how many minutes it takes to cover one kilometre. Runners typically use pace; cyclists and most other sports use speed.

Converting between the two is simple in concept — pace (seconds/km) = 3600 ÷ speed (km/h) — but doing it quickly in your head with minutes and seconds is error-prone. This converter handles both directions instantly. Enter a pace like 5:30/km and get 10.91 km/h. Enter 12 km/h and get 5:00/km.

This converter also shows projected race finish times for 1 km, 5K, 10K, half marathon, and full marathon based on your pace — so you can quickly answer "if I run at this speed, when will I finish?" It supports both metric (min/km) and can be compared in mph and min/mile for runners used to imperial units.