Running Pace Calculator: Pace per Mile and Km, Speed and Splits

Pace is the time it takes you to cover one mile or one kilometer, written in minutes and seconds, such as 9:39 per mile. Speed is the same thing turned around, the distance you cover in an hour, such as 6.2 mph. Race splits and course markers come in miles or kilometers, so runners plan in pace, while treadmills are set in speed, so most runners need both.

This calculator converts between them for a mile, a 5K, a 10K, a half marathon, a marathon or any distance you type in. Enter a finish time to get your pace, speed and even splits, or switch to Time from pace to see the finish time a goal pace gives you. It uses the exact mile from the US National Institute of Standards and Technology's guide to units (NIST SP 811), 1,609.344 meters, and the World Athletics distances for the half marathon (21.0975 km) and the marathon (42.195 km). It does not predict your time at a new distance or set training paces. The race time predictor and the VDOT calculator do those jobs.

How to calculate running pace

Running pace is your time divided by the distance, and speed is the distance divided by your time. To find a finish time, multiply your pace by the distance.

Pace = time ÷ distanceSpeed = distance ÷ time, or 60 ÷ pace in minutesFinish time = pace × distance

Worked by hand, the default 5K in 30:00 takes four steps.

1. Write the time in minutes. 30:00 is 30 minutes. A time with seconds converts the same way, so 1:59:30 is 119.5 minutes.
2. Divide by the distance. A 5K is 3.107 miles, so 30 ÷ 3.107 = 9.656 minutes per mile. In kilometers, 30 ÷ 5 = 6 minutes per km.
3. Turn the decimal into seconds. 0.656 × 60 = 39 seconds, so the pace is 9:39 per mile, or 6:00 per km.
4. Work out the speed. 60 ÷ 9.656 = 6.2 mph, and 60 ÷ 6 = 10.0 km/h.

Going the other way, multiply. At 9:39 per mile, a 10K, which is 6.214 miles, takes 9.656 × 6.214 = 60 minutes. To switch a pace between units, divide a pace per mile by 1.609344 for the pace per km, or multiply a pace per km by 1.609344 for the pace per mile, so 6:00 per km is 9:39 per mile. The calculator rounds paces and times to the nearest second and speeds to one decimal place.

Marathon pace calculator: pace chart for 3:00 to 6:00

Choose Marathon in the calculator and enter your goal time to get your pace and a split for every mile, kilometer and 5K. The chart gives the even pace for finish times from 3 to 6 hours, with the time each 5K takes and your time at halfway. A marathon is 26.219 miles (42.195 km), so every minute you add to your finish time adds about 2.3 seconds to each mile, or 1.4 seconds to each kilometer.

To break 4 hours, you need to average faster than 9:09 per mile5:41 per km and reach halfway before 2:00:00. The chart assumes an even pace. On average, marathon runners slow down in the second half, as the pacing section below shows, so reach halfway on the chart's time rather than ahead of it. Our guide on how to train for a marathon covers the 18 weeks before race day.

Half marathon pace calculator: pace chart for 1:30 to 3:00

A half marathon is 13.109 miles (21.0975 km), exactly half a marathon, so at any pace it takes half as long. That means a sub-2-hour half marathon needs the same pace as a 4-hour marathon, 9:09 per mile5:41 per km. Choose Half marathon in the calculator for your own goal, or read it off the chart.

At an even 9:09 per mile you would finish in 1:59:57, only 3 seconds inside 2 hours,At an even 5:41 per km you would finish in 1:59:54, only 6 seconds inside 2 hours, so aim a second or two faster if 2 hours is the goal. Our half marathon training plan covers 12 weeks of training for a first race, and the race time predictor estimates a realistic goal from a recent 5K or 10K.

5K and 10K pace

A 5K is 3.107 miles and a 10K is 6.214 miles, so at any even pace a 10K takes exactly twice as long as a 5K. The chart turns common paces into finish times for all four race distances, which is what the calculator's Time from pace mode does for any pace you enter.

To estimate your time for a longer race from a recent 5K, allowing for slowing down over the longer distance, use the race time predictor. To compare your time with runners of other ages, the age-graded calculator scores it against the 2025 USATF road standards.

Treadmill speed to pace

Treadmills show speed, while most running plans give pace. To turn mph into minutes per mile, divide 60 by the speed, so 6.0 mph is 10:00 per mile and 7.5 mph is 8:00 per mile. In metric, 60 divided by km/h gives minutes per km, so 10 km/h is 6:00 per km. The chart converts common settings, and the calculator shows the speed for any pace.

The incline column comes from the study below. Jones and Doust tested nothing slower than 6.5 mph (10.5 km/h), so for the slower rows the 0% is our assumption rather than a finding of the study.

Should you set a 1% incline?

Jones and Doust (1996) had nine trained male runners run for six minutes at a time on a treadmill at 0, 1, 2 and 3 percent grades and on a level road, at six speeds from 2.92 to 5.0 meters per second. That is about 6.5 to 11.2 mph (10.5 to 18.0 km/h), or 9:11 to 5:22 per mile. They measured the oxygen each run cost. At the two slowest speeds, 6.5 and 7.4 mph (9:11 and 8:03 per mile), the flat belt cost the same as the road. At 8.4, 9.3 and 10.2 mph (7:09 to 5:51 per mile), the flat belt was easier than the road, and at the fastest speed, 11.2 mph, no grade differed clearly from the road. A 1 percent grade matched the road at every speed they tested, and the authors concluded that it best reflects the energy cost of running outdoors, for runs of about 5 minutes at those speeds.

So at an easy pace slower than about 8:00 per mile (5:00 per km), a flat belt is close to running outside, and at faster paces a 1 percent incline is the closer match. The study tested trained men over a few minutes, so treat it as a guide. Our guide to treadmill vs outside running covers effort, heart rate and the other differences, and the treadmill calorie calculator estimates the calories for any speed and incline.

Even pace or negative splits?

The calculator's splits assume you hold one pace from start to finish, and the research supports something close to that. In a review of pacing in competition, Abbiss and Laursen (2008) concluded that in events lasting longer than about 2 minutes, athletes may perform better when they spread their pace more evenly.

On average, marathon runners slow down instead. Deaner and colleagues (2015) analyzed 91,929 performances in 14 US marathons. On average, men ran the second half 15.6 percent slower than the first and women 11.7 percent slower. Slower finishers slowed the most, and more experienced runners slowed less. In 190,228 New York City Marathon finishes from 2006 to 2011, every group slowed over the race, and the fastest runners varied their speed from one 5K to the next the least (Santos-Lozano et al. 2014).

Since slowing down is so common, aim to reach halfway at your goal pace or a few seconds per mile slower, and speed up only if you feel strong after that. Running the second half at the same pace is an even split, and running it faster is a negative split. Our guides on negative split running and how to pace yourself running show how to practice both.

How accurate is a pace calculator?

The arithmetic is exact. A mile is defined as exactly 1,609.344 meters, and the calculator rounds paces and times to the nearest second, so for a given distance and time, the pace it shows is within half a second of the true figure. The uncertainty is in the distance, and in how well your watch measures it.

GPS watches

Gilgen-Ammann and colleagues (2020) tested eight GPS sport watches on measured routes of 404 to 4,297 meters in town, in a forest and on a track. Their mean absolute errors ranged from 3.2 to 6.1 percent of the distance. The watches mostly read short, except on the track, where six of the eight read a little long, and running gave larger errors than walking or cycling for most watches. A watch that reads 3.2 percent short shows a true 9:39 mile as 9:59, and one that reads 6.1 percent short shows it as 10:17.

Race-day readings were closer in a field study. At a half marathon in Heilbronn, Germany, on a course measured by an accredited measurer, Pobiruchin and colleagues (2017) collected the distances that 179 runners' GPS sport watches recorded. They averaged 21.18 km against the official 21.0975 km, a mean absolute error of 0.12 km, and phones running a tracking app averaged 21.40 km. The authors note that not every runner can follow the ideal racing line. A watch that reads 0.4 percent long, as these did on average, shows a 9:09 mile as 9:07.

Certified courses

Race courses are measured so they are never short. USA Track & Field's rules for course certification treat two requirements as absolute: the course is measured along the shortest possible route, and a short course prevention factor of one part per thousand is added. USATF's course measurement training defines that route as the shortest path a runner could take without being disqualified, measured no more than 30 cm (1 foot) from the curb, and puts the extra 0.1 percent at about 16 feet in a 5K. So a certified race is at least its full distance along the tightest line, and any runner who weaves through a crowd or swings wide on a bend covers more. The 0.1 percent itself changes a 9:39 pace by less than a second per mile.

Hills, heat, wind and altitude change how fast a given effort carries you, but not the arithmetic. To learn a pace you can trust, practice it on a measured route or a running track.

What is a good running pace?

A good pace is one you can hold for the whole distance, and it depends on your age, sex and how long you have been running. Our page on average running speed gives typical paces from large datasets of everyday runs and race results, by age, sex and experience, so this page does not repeat them. If you are new to running, pace yourself by effort before you chase a number. Once you have a recent race time, the VDOT calculator turns it into training paces, such as the pace for a tempo run.

Worked examples: seven runs through the pace calculator

Each row is one entry in the calculator. The bold figure is what the calculator works out: the pace from a finish time, or, in the Time from pace row, the finish time from a goal pace.

Two patterns stand out. A 5K in 30:00 and a 10K in 1:00:00 share one pace, and so do a 2-hour half marathon and a 4-hour marathon, because each pair doubles both the distance and the time. And a pace per km is always the pace per mile divided by 1.609344.

Which running calculator to use

Each running calculator on this site answers a different question.

• Pace calculator (this page). You know the distance and a finish time or goal pace, and want the other, with splits and treadmill speed.
• Race time predictor. You ran one distance and want a likely time at another.
• VDOT calculator. You want easy, threshold and interval training paces from a recent race.
• Age-graded calculator. You want to compare your time with runners of any age and either sex.

When to ignore this calculator

A pace calculator does arithmetic. It cannot tell you whether a pace is safe or sensible for you on a given day. In these cases, put pace targets aside and get advice first.

• Heart or lung conditions. If you have heart disease, chest pain, fainting or unusual breathlessness when you exert yourself, or you take heart medicine, ask your doctor before you train to a pace.
• Pregnancy. Run by how you feel rather than by a pace target, and follow the advice of your obstetric care team.
• Coming back from injury or illness. Build back by time and effort first. A physical therapist or doctor can tell you when faster running is safe.
• Heat, hills, altitude and trails. A pace from a flat, cool road does not carry over. Slow down and run by effort on hot days and on hilly or rough courses.
• Brand-new runners. Run by effort for the first few weeks. A pace target can push you faster than your body is ready for.

Stop and walk if you feel dizzy, faint, sick or unusually short of breath during a run.

Related reading

References

1. Thompson A, Taylor BN. Guide for the Use of the International System of Units (SI). NIST Special Publication 811, 2008 edition, Appendix B.8, factors for units listed alphabetically (mile = 1,609.344 m and mile per hour = 0.44704 m/s, both exact). NIST SP 811, Appendix B.8
2. World Athletics. "Marathon." Discipline page: 26 miles 385 yards (42.195 km). worldathletics.org
3. World Athletics. "Half Marathon." Discipline page: 13.1094 miles (21.0975 km). worldathletics.org
4. Jones AM, Doust JH. "A 1% treadmill grade most accurately reflects the energetic cost of outdoor running." J Sports Sci. 1996;14(4):321-327. doi:10.1080/02640419608727717, PubMed 8887211
5. Abbiss CR, Laursen PB. "Describing and understanding pacing strategies during athletic competition." Sports Med. 2008;38(3):239-252. doi:10.2165/00007256-200838030-00004, PubMed 18278984
6. Deaner RO, Carter RE, Joyner MJ, Hunter SK. "Men are more likely than women to slow in the marathon." Med Sci Sports Exerc. 2015;47(3):607-616. doi:10.1249/MSS.0000000000000432, PMC4289124
7. Santos-Lozano A, Collado PS, Foster C, Lucia A, Garatachea N. "Influence of sex and level on marathon pacing strategy. Insights from the New York City race." Int J Sports Med. 2014;35(11):933-938. doi:10.1055/s-0034-1367048, PubMed 24886929
8. Gilgen-Ammann R, Schweizer T, Wyss T. "Accuracy of distance recordings in eight positioning-enabled sport watches: instrument validation study." JMIR Mhealth Uhealth. 2020;8(6):e17118. doi:10.2196/17118, PMC7381051
9. Pobiruchin M, Suleder J, Zowalla R, Wiesner M. "Accuracy and adoption of wearable technology used by active citizens: a marathon event field study." JMIR Mhealth Uhealth. 2017;5(2):e24. doi:10.2196/mhealth.6395, PMC5350460
10. USA Track & Field. "Rules and Regulations Relevant to the RRTC." Course certification procedures: the shortest possible route and the one-part-per-thousand short course prevention factor are absolute requirements. usatf.org
11. USATF Road Running Technical Council. "Course Measurement Seminar and Training" (Measurement Seminar, 2014, 2nd edition): the shortest possible route, measured no more than 30 cm (1 foot) from the curb, and the short course prevention factor of 1.001. rrtc.net (PDF)

How this calculator differs from typical pace calculators

Most online pace calculators divide a time by a distance and stop there. Few say which mile or marathon distance they use, show pace per mile and per km side by side with treadmill speed, or flag an entry such as 3:30 for a marathon as a typo. Fewer still explain why your watch disagrees with the race, or what the pacing research found about even splits.

This calculator uses the exact mile from NIST and the World Athletics race distances. It shows pace in both units with speed in mph and km/h, lays out even splits for every mile, kilometer and 5K, and works in both directions, from time to pace and from pace to time. It adds the treadmill incline from the 1996 study by Jones and Doust, and its accuracy section reports measured GPS errors and how certified courses are measured.