Pace Calculator & Running Pace Chart
Convert pace, speed and finish time for 5K, 10K, half marathon or marathon, predict your times at every distance with the Riegel formula, and look up the full pace chart from 6:00 to 12:00 per mile.
8:03 /mile
5:00/km · 7.5 mph (12.0 km/h)
Predicted times at this fitness level (Riegel formula)
| Distance | Predicted time | Predicted pace |
|---|---|---|
| 5K | 25:00 | 8:03/mile |
| 10K | 52:07 | 8:23/mile |
| Half Marathon | 1:55:00 | 8:46/mile |
| Marathon | 3:59:47 | 9:09/mile |
Race predictions use Riegel's formula (T2 = T1 × (D2/D1)^1.06), a widely used endurance-fatigue model — actual results vary with training, terrain and conditions. How we calculate →
Pace, speed and time — the same math, three ways
Pace (minutes per mile or per kilometer), speed (mph or km/h) and total time are three views of the same relationship: pace × distance = time. Enter any race distance and your finish time above and the calculator instantly gives you the other two — your exact per-mile and per-kilometer pace, and your speed in both mph and km/h.
Predicting your race time with the Riegel formula
Pete Riegel, a research engineer, published a formula in 1977 that's remained the standard for predicting race times across distances: T2 = T1 × (D2/D1)^1.06. Feed it a known time at one distance and it estimates your time at another, using an exponent (1.06) that captures how pace naturally slows as distance increases — glycogen depletion, fatigue and pacing all play a role.
The calculator uses your entered time to predict all four common road-race distances at once: 5K, 10K, half marathon and marathon.
How accurate is the Riegel prediction?
Riegel-based predictions are widely used but not exact — studies suggest they're roughly 80% accurate on average, and tend to run slightly optimistic for distances longer than a half marathon, since marathon performance depends heavily on fueling and pacing strategy that a pure endurance-fatigue formula can't fully capture. Treat the prediction as a solid training benchmark, not a guarantee.
The full pace chart: 6:00 to 12:00 per mile
Below the calculator is a complete pace chart spanning 6:00 to 12:00 minutes per mile in 15-second increments, cross-referenced against 5K, 10K, half marathon and marathon finish times — so you can look up a target pace directly without doing the multiplication yourself, or see what any given pace works out to across every common race distance.
What this calculator does not do
These are mathematical relationships and a well-tested statistical model — they don't account for your specific training history, race-day conditions, course terrain or elevation, all of which affect real-world performance. Use the numbers as a training reference, not a medical or coaching guarantee.
Frequently asked questions
How do I calculate my running pace?
Divide your total time by the distance you ran. For a 5K (3.107 miles) in 25:00, that's 25 minutes / 3.107 miles = 8:03 per mile. The calculator above does this instantly from your race time.
How do I predict my marathon time from a 5K?
Use Riegel's formula: predicted time = your 5K time x (marathon distance / 5K distance)^1.06. A 20:00 5K predicts a marathon of roughly 3 hours 12 minutes — the calculator runs this automatically for all major distances.
What pace do I need to run a sub-2-hour half marathon?
You'd need to average about 9:09 per mile (13.1 miles in under 2:00:00) — check the full pace chart above for the exact time at any 15-second pace increment.
Is a pace calculator accurate for predicting race times?
The Riegel formula used in most pace/race calculators is roughly 80% accurate on average and tends to be a bit optimistic for distances beyond a half marathon, since marathon performance depends heavily on pacing and fueling strategy.
How do I convert running pace to speed?
Divide 60 by your pace in minutes per mile to get mph (a 6:00/mile pace = 60/6 = 10 mph). The calculator converts automatically between pace and speed in both imperial and metric units.
What is a good running pace for a beginner?
Beginner paces vary widely, commonly in the 10:00-13:00 per mile range for an easy effort. The full pace chart above lets you look up finish times across that entire range for every common race distance.
Researched & verified by the Calcuris Data & Research Team. How we build and check our tools →