Pace, time and distance are three views of the same equation. Give this calculator any two and it solves the third, then predicts how that effort translates to a different race distance.
Free fitness tool
Pace Calculator
Solve for pace, time or distance, with race-distance presets, and predict a race time at another distance.
Runs entirely in your browser. Nothing you enter is sent anywhere.
How the race-time prediction works
The predictor uses Riegel's formula (Peter Riegel, 1977): T2 = T1 x (D2 / D1)^1.06. It's the same maths race-prediction tools have used for decades, built on the observation that pace naturally slows over longer distances at a fairly consistent rate for a trained runner. It works best when predicting a distance reasonably close to one you've actually raced, an all-out 5K predicts a 10K well; using it to jump from a 5K straight to a marathon prediction stretches past what the formula was validated on, and factors like fueling, pacing discipline and heat management start to matter more than raw fitness the longer the race gets.
Pace calculator FAQ
How do I calculate my running pace?
Divide your total time by the distance covered. This calculator does it for you, and can also work backward: give it a pace and distance to find your finishing time, or a time and pace to find how far you went.
What is a good 5K or 10K pace for a beginner?
There is no universal number, it depends entirely on your own fitness, but many beginner runners land somewhere around 6 to 7 minutes per kilometer (roughly 10 to 11 min/mile) for a 5K, finishing in 30 to 35 minutes. The honest goal for a first race is usually finishing strong and consistent, not hitting a specific pace.
How accurate is the race time predictor?
Riegel's formula works best predicting a nearby distance from a real recent race result, a 5K predicting a 10K, for example. Stretching it across a much bigger jump, a 5K predicting a marathon, is less reliable, since fueling, pacing discipline and heat management start to matter more than raw fitness the longer the race gets.
What is the difference between pace and speed?
Pace is time per unit distance (minutes per kilometer or mile), speed is distance per unit time (kilometers or miles per hour). Runners typically think in pace, cyclists and drivers typically think in speed, this calculator shows both.
Is my data private?
Yes. Every calculation runs in your browser. Nothing you enter is sent to a server, logged, or stored.
Free pace calculator by ANUPRESS
Pace is the number that actually plans a race
Total finish time tells you the goal, pace tells you how to execute it, the per-kilometer or per-mile number you actually watch on a wrist during the race itself. Working from a known pace also makes splits trivial: if 5:00/km is the target, the 10K checkpoint should read 50:00, no mental math mid-run required.
The race predictor has real limits, and they matter
Riegel’s formula (1977) works best predicting a nearby distance from a recent real result, a 5K predicting a 10K is a reasonable use. Stretching it much further, using a 5K time to predict a marathon, asks the formula to extrapolate well past what it was built for: fueling strategy, pacing discipline and heat management all start to matter more than raw fitness the longer a race gets, and none of that shows up in a simple exponent.
Training pace versus race pace
Most structured training plans define paces relative to a recent race result, easy runs meaningfully slower than race pace, tempo runs closer to it, intervals faster. Once you have a real recent time from any distance, this calculator’s prediction gives you a reasonable target pace for a goal race still weeks away, useful for planning long runs and workouts around, not just for race day itself.