Written by Sarah Mitchell · Reviewed by Alex Chen · July 28, 2026
Calculate pace, speed, distance, or time for running, cycling, and walking.
Enter values and click Calculate.
Running conversations mix four numbers: pace, speed, time, and distance. Pace is how long one unit of distance takes, speed is how much distance one hour covers, and the other two are the inputs that produce both. This calculator accepts any two of the four values and fills in the remaining pair, so a single page covers planning a workout, checking a race result, or estimating how long a route will take.
Choose the mode that matches what you know, then fill in exactly two fields and leave the others empty. In Pace mode you enter a distance and a time, and the page returns your pace and speed. In Speed mode you give a speed and a time, and it returns the distance covered. Time and Distance modes work the same way in reverse: supply the two values you have, and the calculator derives the ones you are missing.
Distance and speed are set in miles or kilometers with the toggle, and pace is displayed as minutes and seconds per unit. Whatever units you pick, the calculator keeps them consistent, so a kilometer-per-hour speed and a kilometer distance work together naturally.
Suppose you finish a 10-kilometer race in 52 minutes and 30 seconds. Enter 10 for the distance and 52:30 for the time, then read the results. Your pace is 5:15 per kilometer: the 3150 total seconds spread evenly across 10 kilometers means 315 seconds each, and 315 seconds is exactly five minutes and fifteen. Your speed is 11.43 kilometers per hour, because 10 kilometers divided by 0.875 hours lands just over eleven and a half kilometers in a full hour.
Flip the unit toggle to miles and the same run tells a different story. The 10K is roughly 6.2 miles, so the pace becomes 8:28 per mile and the speed reads about 7.09 miles per hour. Both views describe the identical effort, just expressed in the units your plan calls for.
Pace mode is the training staple: pick a goal time for a set distance and the calculator tells you the pace to hold. Time mode answers "how far can I go in forty minutes at an easy pace" by turning the pace into distance. Speed mode suits treadmill work, where the machine displays a number per hour and you want to know the equivalent pace. Distance mode lets you check whether your planned route fits the time you have, given the speed you expect to sustain.
One mile equals 1.609344 kilometers, and the page's unit toggle applies that conversion to the results automatically. The relationship is useful to know even outside the calculator: 8:28 per mile and 5:15 per kilometer are the same pace, and rounding 1.61 makes rough conversions easy to do in your head. A marathon course measures 26.2 miles or 42.2 kilometers, and a 5K race is 3.1 miles, so the numbers appear constantly in race listings.
The familiar race ladder maps cleanly onto the calculator. A 5K is 3.1 miles, a 10K is 6.2 miles, the half marathon is 13.1 miles, and the full marathon is 26.2 miles. Enter any of these with a target time in Pace mode to get the per-unit pace you would need to hold. For example, a 2:00:00 half marathon works out to about 9:10 per mile, while the same distance in 1:45:00 drops to roughly 8:00 per mile.
Because that is how runners read it. The calculator splits the total time by the distance and formats the result as a clock-style reading, so a pace of 5:15 means five minutes and fifteen seconds per kilometer rather than a decimal fraction.
Only the two empty fields are treated as the unknowns. The calculator uses the filled values to compute them and ignores the contradiction, so you should leave blank exactly the pair you want answered.
Keep them consistent. The unit toggle applies to the whole page, so enter a kilometer distance with kilometer-per-hour speed, or miles with miles per hour, and the results stay coherent.
They are inverses of each other. Pace measures time per distance, like 5:15 per kilometer, while speed measures distance per hour, like 11.43 kilometers per hour. The calculator always shows both because different plans are written in different units.
Yes. The math applies to any distance over time, so a walker or cyclist can enter their own numbers and get the same pace and speed readouts.
The real value of the page is moving between a goal and a plan. Start from the race you are training for, use Pace mode to find the target pace, then use Time mode to see how far your easy days should cover at a slower pace. Long-run weekdays, tempo sessions, and recovery jogs each have their own pace band, and converting between them becomes a two-step job instead of a guess. All the arithmetic happens in your browser, so no training data leaves this page.
A flat road pace does not survive contact with hills, wind, or heat. Climbing a steady grade costs more energy per kilometer, so most runners add a few seconds per unit on ascent and take some back on the downhill. A strong headwind punishes the same way, while altitude thins the air and forces the heart to work harder for the same speed.
Coaches treat the adjusted figure as a realistic target rather than an ideal one. Tempo sessions settle into a comfortably hard effort, intervals alternate fast bursts with easy jogs, and recovery runs drift well below race pace. Cadence, stride length, and effort level all interact, and the calculator's pace output gives you a number to steer by even when the terrain disagrees.