Running Pace Calculator
Turn a finish time and distance into your pace per mile and per kilometer, or flip it around to predict a finish time from a target pace.
These numbers assume an even pace the whole way. Most beginners run the second half a little slower than the first, so treat this as a target, not a guarantee.
How it works
Pick a distance (a preset like 5K or half marathon, or your own custom number in kilometers), then choose a direction. "Pace from finish time" takes a goal or past result and divides it by the distance to get your pace per mile and per kilometer. "Finish time from pace" goes the other way: give it a target pace and it multiplies that out across the distance to show what finish time you'd land on.
Worked example: say you ran a 5K (3.10686 miles) in 30:00. That's 1,800 seconds divided by 3.10686 miles, which comes out to 579 seconds per mile, or 9:39. The same math against 5 kilometers gives 360 seconds per km, or 6:00. Flip it around and enter a 9:39 mile pace over that same 5K distance, and the calculator multiplies it back out to the original 30:00 finish. This is the same conversion runners do in their heads at the finish line, just faster and without the arithmetic mistakes that creep in when you're tired.
FAQ
Why does it show pace per mile and per km at the same time?
Race distances in North America are usually posted in miles, but a lot of GPS watches and training plans default to kilometers, or your race is a 5K or 10K measured in metric. Seeing both means you don't have to convert mid-run when a mile marker doesn't match what your watch is showing.
My race finish time didn't exactly match what I typed in.
The calculator rounds pace to the nearest second, so multiplying that rounded pace back out by the distance can land a second or two off the original time. That's expected and not worth worrying about, since your actual pace varies by more than a second per mile anyway.
Should I aim for an even pace the whole race?
For a first race, no. Most beginners do better starting a little slower than their target pace and holding steady, rather than going out fast and fading. Use this calculator to know your target, then check your watch every mile or two to stay close to it instead of chasing a number that drifts the moment you get tired.
What if my custom distance isn't a round number?
Enter it in kilometers with as many decimal places as you know, for example a 7.5K fun run or a course you measured yourself. The math works the same regardless of how tidy the number is.
For more on choosing and hitting a target pace, see how to find your easy conversational pace, why running slow is the fastest way to improve, and how to train for your first 5K.