Running Pace Calculator
Work out your running pace and speed from distance and time.
Results update as you type.
About this calculator
A running pace calculator converts a distance and a finish time into your pace per kilometre or mile, and your average speed. Pace is the total time divided by the distance, and speed is the distance divided by the time. Use the tabs to instead solve for the finish time from a distance and a target pace, or for the distance you would cover at a given pace and time.
For example, running 10 km in 50 minutes is a pace of 50 ÷ 10 = 5:00 per kilometre and an average speed of 12 km/h. The calculator also shows the equivalent pace per mile and predicts your 5K, 10K, half-marathon and marathon times from that effort using the Riegel formula.
Use it to plan race splits, lock in a target pace for a training run, or convert between minutes-per-mile and minutes-per-kilometre. Enter any two of distance, time and pace and it solves for the third.
Frequently asked questions
How is running pace calculated?
Pace is total time divided by distance. A 50-minute 10 km run is 50 ÷ 10 = 5:00 per kilometre. Speed is distance divided by time in hours.
Can I solve for time or distance instead?
Yes. Use the Time tab to enter a distance and a target pace and get the finish time, or the Distance tab to enter a pace and a time and get how far you would run.
What is a good running pace?
It depends entirely on fitness and distance. Focus on your own trend over time rather than comparing to others.
How do I convert pace between miles and kilometres?
Multiply a per-mile pace by 0.6214 to get per-kilometre, or divide by it to go the other way, since a mile is about 1.609 km. The calculator shows both automatically as the "pace" and "pace (other unit)" results.
How does it predict my race times?
It uses the Riegel formula, which scales a known time to another distance with T2 = T1 × (D2 ÷ D1) raised to the power 1.06. That power adds a small slowdown for longer races, so your marathon prediction is more than four times your 10K time.
How do I work out my average speed from pace?
Divide the distance by the time in hours. A 10 km run in 50 minutes (0.833 hours) is 10 ÷ 0.833 = 12 km/h. The calculator reports this average speed alongside your pace.
What pace do I need for a sub-2-hour half marathon?
A half marathon is 21.1 km, so under 2 hours means faster than about 5:41 per kilometre or 9:09 per mile. Use the Time tab with your target pace to see the finish time it produces.
API — use this calculator from code
Call this calculator as a free JSON endpoint — no key required. Send the field values below as query parameters or JSON. Read the full API docs →
Endpoint
GET https://calculator.free/api/v1/running-pace/curl
curl "https://calculator.free/api/v1/running-pace/?distance=10&dist_unit=km&minutes=50&pace_min=5&pace_sec=0&_mode=pace"JavaScript fetch()
const r = await fetch(
"https://calculator.free/api/v1/running-pace/?" + new URLSearchParams({
"distance": "10",
"dist_unit": "km",
"minutes": "50",
"pace_min": "5",
"pace_sec": "0",
"_mode": "pace"
}));
const data = await r.json();
console.log(data.results);Results are estimates for general guidance only, not financial, medical or tax advice.