Pace Calculator

pace per kilometre = (time in seconds ÷ distance in kilometres) ÷ 60; pace per mile = pace per kilometre × 1.609344; speed in km/h = distance ÷ (time ÷ 3600)

time

Your finish time converted to seconds. 50:00 becomes 3000, and the two-part form is what runners write; the three-part form H:MM:SS is accepted as well, so a marathon written 3:30:00 is read as three hours and thirty minutes rather than three minutes and thirty seconds (seconds)

distance

The distance converted to kilometres, because that is the figure every output is derived from. Enter a race in miles and it is converted first — 26.2 miles becomes 42.16 kilometres, which is why a mile-based entry and a kilometre-based entry of the same race agree to the last decimal (km)

1.609344

The kilometres in a mile, exactly. It is a definition rather than a measurement, so the mile figure is the kilometre figure multiplied by it and not a separately rounded second answer — the two paces can never disagree about how fast you ran (km)

pace per kilometre

Minutes as a decimal, not minutes and seconds: 5.50 means five and a half minutes, the figure runners on this site see on the speed and distance page as well. The chart below prints the colon form instead, because a table is scanned by eye and 5:30 is what a scan can find (minutes)

speed

Distance divided by time in hours — the same two numbers as the pace, inverted. It is the unit a treadmill console and a cycling computer use, which is the only reason it is here: nobody plans a run in kilometres per hour (km/h)

Use it before a run to turn a target pace into a target time, and after one to find out what pace you actually held. The chart is the forward direction and the two pace outputs are the backward one, so both questions are answered without re-entering anything. Do not use it to plan a race you have not trained for: pace over a full marathon is not the pace you hold in training, and the chart will happily print a finish time that is arithmetically perfect and physically impossible. For the reverse question — how long a given speed takes over a given distance, in decimal hours rather than minutes and seconds — the speed distance time calculator on this site takes the same inputs in a different shape.

1. 10 kilometres in 50 minutes

   1. 50:00 becomes 3000 seconds
   2. 3000 ÷ 10 = 300 seconds per kilometre, and 300 ÷ 60 = 5.00 minutes per kilometre
   3. 5.00 × 1.609344 = 8.05 minutes per mile
   4. 10 ÷ (3000 ÷ 3600) = 12.00 kilometres per hour
   5. 12.00 ÷ 1.609344 = 7.46 miles per hour

   The combination the page opens with, so a fresh screen shows exactly these four numbers. It is also the easiest one to check against a treadmill: 12.0 km/h on the console is this run. Note that the pace is printed as 5.00 rather than 5:00 — the decimal form is the one this site's speed and distance page uses for the same quantity, so the two pages cannot disagree about what a pace is.

2. A marathon in 3:30:00

   1. 3:30:00 becomes 12600 seconds — the three-part form is read as hours, minutes and seconds
   2. 12600 ÷ 42.195 = 298.6 seconds per kilometre
   3. 298.6 ÷ 60 = 4.98 minutes per kilometre
   4. 4.98 × 1.609344 = 8.01 minutes per mile
   5. 12600 ÷ 3600 = 3.5 hours, and 42.195 ÷ 3.5 = 12.06 kilometres per hour

   Read the last two digits of the pace carefully, because this is the example that shows why the exact distance matters. 42.195 is the defined marathon distance, not 42.2 rounded — over the full race those five metres are worth about a second and a half, which is exactly the kind of margin a qualifying time turns on. Type 42.2 instead and the pace moves from 4.98 to 4.97, and the finish time the chart predicts for that pace stops matching the one you ran.

3. 5 kilometres in 25:30

   1. 25:30 becomes 1530 seconds
   2. 1530 ÷ 5 = 306 seconds per kilometre, and 306 ÷ 60 = 5.10 minutes per kilometre
   3. 5.10 × 1.609344 = 8.21 minutes per mile
   4. 5 ÷ (1530 ÷ 3600) = 11.76 kilometres per hour
   5. 11.76 ÷ 1.609344 = 7.31 miles per hour

   The case with a half minute in it, which is where the colon form earns its place: 25:30 on the watch is a single value, and the seconds convert with it. Convert the whole thing to seconds first and there is no rounding decision to make — a page that rounded the minutes and dropped the seconds would report 25:00 and be 30 seconds out over a distance this short.

4. A beginner's 5 kilometres in 30:00

   1. 30:00 becomes 1800 seconds
   2. 1800 ÷ 5 = 360 seconds per kilometre, and 360 ÷ 60 = 6.00 minutes per kilometre
   3. 6.00 × 1.609344 = 9.66 minutes per mile
   4. 5 ÷ (1800 ÷ 3600) = 10.00 kilometres per hour
   5. 10.00 ÷ 1.609344 = 6.21 miles per hour

   Round numbers, and a useful landmark: six minutes per kilometre is the pace most beginner plans settle on, and the chart's 6:00 row reads straight across to a 30:00 5K, a 1:00:00 10K and a 2:06:35 half marathon. That last figure is the one worth looking at — the halfway distance is where a pace that feels comfortable in training stops being a prediction and starts being a target you have to hold.

This page is arithmetic, and arithmetic cannot tell you whether the pace is one you can hold. The figures assume even pacing: the same pace from the first kilometre to the last, which is not how races are usually run. Most runners start faster than they finish, and the slowdown is larger the longer the race, so a marathon pace taken from a half marathon will produce a finish time that is optimistic by several minutes rather than seconds. Terrain, wind, heat and hills are all outside the calculation, and so is the difference between a flat measured course and a loop around your neighbourhood that your watch rounds to the same distance. Second, the chart's rows only go where it goes: paces from 3:00 to 7:00 per kilometre in 30-second steps. A pace outside that range is a correct answer on this page but has no row to read across, and the halfway and marathon columns are the ones where extrapolating by hand goes wrong fastest. Third, the distances in the chart are road-race distances, so 21.0975 and 42.195 are the measured course figures rather than the nominal ones — a race advertised as a half marathon is expected to be that distance, and one that is not is a course measurement problem rather than a calculator problem. Finally, nothing here accounts for the fact that a mile is 1.609344 kilometres by definition but a mile of your local loop is whatever your watch says it is.

What is the difference between pace and speed?

They are the same measurement written two ways. Pace is how long one unit of distance takes — five minutes per kilometre — and speed is how much distance one unit of time covers — twelve kilometres per hour. Divide the distance by the time and you have speed; divide the time by the distance and you have pace. Runners use pace because a training session is planned in minutes per kilometre, and machine consoles use speed because that is what their displays are built around. This page prints both, in kilometres and in miles, so you never have to convert between them by hand.

Why is my pace shown as 5.50 instead of 5:30?

Because 5.50 minutes is five and a half minutes, which is the same thing as 5:30 — the decimal form is not a different quantity, only a different notation. The site's speed and distance calculator prints paces this way too, and the two pages agreeing about what a pace looks like matters more than either notation on its own. The chart on this page uses the colon form because a table is scanned rather than typed into, and 5:30 is easier to find with your eye.

How do I work out marathon pace from a half marathon?

Take the half marathon pace this page gives you and add roughly five to fifteen seconds per kilometre, more if the marathon course is hillier or the day is warmer. Doubling the half marathon time is the older rule of thumb and it is optimistic for most runners: the slowdown over the second half is real, and it grows with the distance. Enter your intended marathon pace in the calculator and the chart will show the finish time it produces, which is a target you can then compare against your training runs rather than against a race you have not run.

What is a good 5k pace?

There is no single answer, and the honest version is that a good 5k pace is one you can hold for the whole 5 kilometres without slowing in the last one. As a landmark, six minutes per kilometre finishes in 30:00 and five minutes per kilometre finishes in 25:00; club runners commonly race somewhere between four and five. Enter the pace you can hold, read the 5K column, and you have a target rather than a guess. If you cannot hold it, the pace is wrong and not the chart.

Does the calculator round my time?

No. Your time is converted to seconds as a whole number and every figure is computed from that, so a time with seconds in it keeps them. What is rounded is the display: the pace and speed outputs are shown to two decimal places. That matters only at the last digit — 4.98 minutes per kilometre is 4 minutes 58.8 seconds, and over a marathon that rounding is worth a few seconds of finish time rather than minutes.

Why does the chart stop at 7:00 per kilometre?

Because a chart is only useful while the rows are distinguishable from one another. Thirty-second steps from three to seven minutes cover everything from a fast club runner to a comfortable beginner, and beyond seven minutes per kilometre the run is usually a walk-run or a recovery session where a printed target is not what you are working from. If your pace falls outside the range the calculator still answers correctly — you simply read it off the outputs instead of the chart.

Should I enter a race distance or what my watch measured?

The race distance, if you raced it. A certified course is measured along the shortest possible path, so a watch reading almost always comes out slightly long — the extra is the bit you spent running wide around corners and weaving through people. That difference is one to two per cent, which over a marathon is half a minute or more of pace. Enter what the course was, and the pace you get is the pace you raced; enter the watch reading and you will conclude you were slower than you were.

• Describing and understanding pacing strategies during athletic competition — Abbiss CR, Laursen PB — Sports Medicine, 2008;38(3):239-252 — the review that names the pacing patterns (even, positive, negative) and the finding that faster runners hold a more even pace than slower ones, which is the reason the limitations section warns that a pace taken from a shorter race is optimistic
• Book of Rules — Competition Rules and Technical Rules — World Athletics — the technical rules that define the road race distances this page's chart is built on: the half marathon as 21.0975 kilometres and the marathon as 42.195 kilometres, measured on the course rather than announced as a round number