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Running Pace Calculator — 5K, 10K, Half Marathon and Marathon Splits
Your next finish line, calculated — 5K · 10K · half marathon · marathon · race splits · interval planner · export & share. Free, no signup.
Find the pace for your race goal
Running pace is the time it takes to cover one kilometer or one mile. The whole tool rests on pace = time ÷ distance. A 50-minute 10K needs 5:00/km; a 25-minute 5K needs exactly the same pace. Pick a race preset or type any distance you like.
Switch to Finish time and it runs the other way, time = pace × distance. Splits are computed from the unrounded pace so rounding never accumulates down the table — displayed times are rounded to the nearest second only at the moment they are printed. If you are chasing a strict "sub" time, the finish-ahead buffer shifts the target so you cross the line early rather than exactly on it.
Build an interval session
Enter the repetition distance, the pace you want to hold for each rep, and the recovery between them. Add a timed warm-up and cool-down and you get the whole session laid out, rep by rep, with cumulative elapsed time.
Six 400 m reps at 5:00/km is 2:00 per rep. With five 90-second recoveries, a 10-minute warm-up and a 5-minute cool-down, the session totals 34:30. The recovery after the last rep is deliberately not counted — you are finished, not resting.
What this will not tell you
These are arithmetic results, not predictions of your fitness. They assume one constant pace for the whole distance and know nothing about hills, wind, heat, traffic lights or how your legs feel at 30 km. Every pace here is one you typed in yourself. Treat the numbers as a plan to run against, not a forecast of what will happen.
Everything is calculated on your own device. Nothing is uploaded, there is no account, and the share link puts your settings in the URL rather than on a server.
Running pace calculator FAQ
What pace do I need for a 5K or 10K?
Divide your finish time by the distance. A 25-minute 5K and a 50-minute 10K both need 5:00 per kilometer (about 8:03 per mile). Choose Target pace and enter your own goal.
What pace do I need for a sub-2-hour half marathon?
A half marathon is 21.0975 km. Exactly two hours requires approximately 5:41.3/km. To aim below two hours, select the half marathon preset, enter 2:00:00 and add a buffer; one minute under gives approximately 5:38.4/km.
What pace do I need for a four-hour marathon?
A marathon is 42.195 km. Four hours requires approximately 5:41.3 per kilometer or 9:09.3 per mile. A strict sub-four-hour goal needs a slightly faster pace; use the finish-ahead buffer.
Can I switch between kilometers and miles?
Yes. Distance units convert your existing distance. Running pace and split units can be chosen independently. One mile is exactly 1.609344 kilometers.
Are the finish times predictions of my fitness?
No. These are arithmetic results assuming a constant average pace. They do not account for terrain, stops, weather, or changes in speed. Interval paces are entered by you rather than prescribed by the calculator.
Does the interval total include recovery and warm-up?
Yes. Total time includes the warm-up, every running rep, recovery between reps, and the cool-down. There is no recovery after the last rep. Distance totals include running reps only; timed warm-up, cool-down and recovery distances are not estimated.
Can I save or share my running plan?
Copy plan link stores your settings in the URL fragment so you can bookmark it or send it to someone. Export CSV downloads the split or interval table. Print plan opens a clean printable version. No account is needed.