Running Pace & Race Time Calculator
Turn distance, pace or finish time into a simple pacing plan
Running pace, race time and training FAQ
What does “pace” mean in running?
Pace is how long you take to cover a set distance, often shown as minutes per mile or minutes per kilometre. If you run 5 km in 25 minutes, your pace is 5:00 per km; if you run a mile in 9:00, your pace is 9:00 per mile.
How is pace different from speed?
Pace is time per distance, speed is distance per time. A pace of 8:00 per mile equals about 7.5 mph (around 12.1 km/h). Many runners like pace for workouts and speed for treadmills or bikes—this tool shows both so you can switch easily.
What is a “good” running pace?
There is no universal good pace. It depends on experience, age, terrain, distance and goals. A 12:00 per mile pace can be an easy jog for one runner and a strong race effort for another. Compare new runs to your own recent efforts rather than to other people.
How can I use this for race planning?
Enter a realistic goal time or a recent race pace, then check the per-mile or per-kilometre pace and the simple split checkpoints. You can use those numbers to decide if a negative split (slightly faster second half) or even pacing feels appropriate for your course and fitness.
How accurate will my predicted race performance be?
Conversions assume that you can hold a steady effort over the full distance. Reality is messier. Heat, wind, hills, fuelling, sleep and nerves all matter. Treat these numbers as a ballpark guide, then adjust for conditions and your training history.
How does this relate to training paces?
Many plans use pace zones like easy, tempo or interval. Knowing your realistic race pace lets you anchor those zones; for example, long runs often sit 30–90 seconds per mile slower than marathon pace. A separate training-pace or VO₂ calculator can turn your race pace into detailed workout ranges.
Who should be careful using race calculators?
If you are new to running, returning after injury or illness, pregnant, or managing heart, lung or metabolic conditions, use conservative paces and check in with your healthcare team. Err on the easy side until you know how your body responds.
How to use this running pace and race time calculator
This page turns “I ran about X for Y distance” into clear pace, speed and simple checkpoints. Instead of guessing at race goals, you can use a recent effort or a realistic target to see what each mile or kilometre will roughly look like.
1. Pick your units and race distance
Start by choosing the units you think in. The tool loads with US-first (miles and min/mi), but you can switch to kilometres and min/km if that’s how you track runs. When you switch units, the race list updates so that 5K and 10K show their matching distance in miles or kilometres instead of implying anything wild like “5K miles”.
2. Decide whether you know time or pace
Often you either know your finish time for a race or your usual average pace from the watch. Set “What do you know?” to match. For finish time, add your hours, minutes and seconds into the time bar. For pace, type something like 8:30 for 8 minutes 30 seconds per mile or kilometre.
3. Read off pace, speed and splits
Hit Calculate pace and time to see:
- Your race distance and total time in a clean format.
- Pace per mile and per kilometre, no matter which units you picked.
- Average speed in mph and km/h.
- Simple split checkpoints (25%, halfway, 75% and finish) so you know what the clock might read at key markers.
You can copy the summary into your training log, a race plan document or a note on your phone to have it handy on race day.
4. Combine this with effort and conditions
Numbers are only part of pacing. Think about how hard the effort feels, the course profile, the weather and where you are in your training cycle. You may choose to aim for the slower end of a range on a hot or hilly day and save the sharp end for cool, flat races where you’re well rested.
If you are unsure how aggressive to be, bring these numbers to a coach or experienced friend and ask whether they match your current fitness. It is almost always better to start a little easier and finish strong than to chase a fantasy pace and fade hard in the final miles.
How the running pace and race time math works
Under the hood, the calculator uses straightforward distance–time relationships. It converts distances between miles and kilometres, normalises everything to seconds, and then derives pace and speed from there.
1. Converting distance between miles and kilometres
Standard race distances are treated as:
- 5K: 5.00 km (≈3.11 miles).
- 10K: 10.00 km (≈6.21 miles).
- Half marathon: 21.0975 km (≈13.11 miles).
- Marathon: 42.195 km (≈26.22 miles).
Custom distances are kept in the units you choose (miles or kilometres), then converted internally using 1 mile ≈ 1.609 km.
2. From finish time to pace and speed
When you enter a finish time, the tool turns it into total seconds. Pace is then:
Pace (sec per km) = total time (sec) ÷ distance (km)
Pace (sec per mile) = total time (sec) ÷ distance (miles)
Those per-kilometre and per-mile paces are converted into mm:ss format. Speed is just distance divided by time in hours, giving mph and km/h.
3. From pace to finish time
When you supply a pace, the tool first treats it as either per mile or per kilometre based on your selected units. It then converts to the other unit and multiplies by the full race distance:
Finish time (sec) = pace (sec per unit) × distance (in that unit)
Total seconds are formatted into hh:mm:ss. The same time is used to recompute speed and cross-check the opposite pace unit.
4. Building simple split checkpoints
For quick pacing checks, the calculator multiplies total time by 0.25, 0.5 and 0.75 to show what the clock might read at 25%, halfway and 75% of the distance, assuming steady pace. These are rounded to the nearest second to keep things easy to remember on the move.
Real races involve surges, hills and fatigue, so treat the output as guide rails, not strict instructions. Adjust them with your coach or healthcare team if you are building up cautiously or training around health considerations.
References and further reading on running pace and race planning
These resources walk through pace, speed and race-time ideas in more depth:
- Runner’s World — How to calculate your paces for running — explains how to turn recent efforts or time trials into realistic race and workout paces.
- SportCoaching — How to calculate pace for running — shows examples of converting between distance, time and pace for common race distances.
- V.O2 — Pace calculator and VDOT overview — describes how pace calculators link to training paces and performance predictions.
Use these for background reading, then combine this calculator’s numbers with your own experience, training log and any coaching or medical advice you already have.