Running Pace Calculator

Your running pace is the single most useful number in your training log, whether you're chasing a 5K personal best or working out a realistic marathon goal. Here's how to calculate it, convert it between km and miles, and use it to plan a race.

How to Calculate Your Running Pace

To calculate running pace, divide your total time by your total distance. If you ran 5 kilometers in 25 minutes, your pace is 5 minutes per kilometer (25 ÷ 5 = 5). The calculator above does this instantly, and converts your result to pace per km, pace per mile, and average speed in one step. Your easy-run pace also lines up with your heart rate training zones — a conversational easy pace usually sits in Zone 2, while goal race pace pushes closer to Zone 4.

How to Convert Running Pace Between Km and Miles

Since 1 mile ≈ 1.60934 km, multiply your per-km pace by 1.60934 to get pace per mile, or divide your per-mile pace by 1.60934 to get pace per km. A 5:00/km pace converts to roughly 8:03/mile. The unit toggle above switches between the two automatically.

Reading the Marathon Pace Chart

The pace chart above shows exactly how a small change in pace affects your marathon or half marathon finish time. Shaving just 15 seconds off your per-kilometer pace can take 10 minutes or more off a full marathon finish, since that difference compounds over 42.195 kilometers.

How to Use It to Set a Race Goal

1. Pick your goal finish time first, then switch to "Predict Finish Time" or use the chart to see the exact pace you'll need to hold.
2. Practice that goal pace in training runs — often called tempo runs — so it feels automatic rather than something you're calculating mid-race.
3. Aim for a slight negative split, running the second half a touch faster than the first, since going out too aggressively usually costs more time late than it gains early.

5K, 10K, and Half Marathon Pace Tips

Shorter races reward a faster, more aggressive pace than a marathon, since you don't need to conserve as much aerobic base for the closing miles. Many runners can hold a 5K pace noticeably quicker than marathon pace, while 10K pace — closer to threshold pace — usually sits in between. Cadence and stride length both influence pace independently of raw fitness, which is why two runners with a similar VO2 max can post different times over the same distance.

Pair It With

Pace is one piece of the training picture. Check your Calorie & TDEE Calculator to make sure you're fueling your training properly, and use the Water Intake Calculator to stay hydrated through long runs and race day.