Running Pace Calculator
Free running pace calculator. Convert pace to finish time (or vice versa) for any distance, plus mile and km splits for 5K, 10K, half, and marathon.
Quick answer
Pace (min/mile) = total time ÷ distance. Finish time = pace × distance. To run a sub-4 marathon (26.2 miles) you need a 9:09/mile pace. Splits get faster on negative-split races, where the second half is faster than the first.
Running Pace Calculator
Pace
How it works
Pace = total time ÷ distance. The calculator converts between miles and kilometers (1 mile = 1.609 km), so you can enter your run in either unit and see your pace per both. Speed is the inverse: distance per unit of time.
When to use it
Planning a race target, comparing training runs, or converting a treadmill pace from one unit to another. Most US 5K and marathon races report results in minutes per mile; international and track events use minutes per km.
Common mistakes
Pace and speed are inverses of each other, but they're easy to mix up. A faster runner has a *lower* pace (fewer minutes per mile) and a *higher* speed (more miles per hour).
How the running pace calculator works
The basic conversion is pace = time ÷ distance. The calculator handles minutes-and-seconds notation (e.g., 8:30/mile) by converting to seconds first, dividing, then converting back. It computes mile splits and kilometer splits side-by-side, plus projected finish times for standard race distances (5K, 10K, half marathon, marathon) at your chosen pace. Going the other way: enter a target finish time and distance, and the calculator backs into the required average pace.
When to use it
Setting a target pace for a race based on your goal time. Splitting a run into mile-by-mile pacing for negative splits. Translating between mile pace (US) and kilometer pace (everywhere else). Planning interval workouts where each interval has a target time. Predicting your race finish if you're trained at a known easy pace.
Common mistakes
- Pacing your race like your training runs. Easy training pace is typically 1:00-1:30 slower per mile than race pace for distances over 10K. Don't anchor on training pace as the realistic race pace.
- Banking time early. Running the first half of a marathon faster than goal pace almost always backfires. The bank evaporates in miles 18-22 with interest. Aim for even splits or a slight negative split.
- Confusing pace with speed. Pace is min/mile (lower is faster). Speed is mph (higher is faster). 7:30/mile = 8 mph. Don't mix them.
Frequently asked questions
How do I calculate my running pace?
Divide total time by distance. For a 30-minute 3-mile run: 30 ÷ 3 = 10 min/mile pace. Or use the calculator above — enter time and distance and it computes pace, splits, and projected finish times for standard race distances.
What pace do I need for a 4-hour marathon?
A 9:09 per mile (5:41/km) pace, sustained for 26.2 miles. That's about 6.6 mph. Most runners need a sub-3:30 marathon training plan to comfortably hit 4:00 — pure pace math underestimates the endurance demand.
How do I run negative splits?
Run the first half of the race 5-15 seconds per mile slower than your goal pace. Pick up gradually around miles 14-18 of a marathon. Most race PRs come from negative splits — your body holds together better when you start conservatively.