Pace Calculator for Distance, Time and Speed

How this pace calculator works

Pace, time, and distance describe the same movement in three different ways. Any two determine the third. Choose the quantity to calculate, then enter the other two. To find pace, the calculator divides time by distance. To find finish time, it multiplies pace by distance. To find distance, it divides time by pace. Speed is the reciprocal view of pace: distance divided by time. These are definitions, so the pace, finish-time, and distance results do not depend on an exercise model or an external formula. Only the separate race time predictor uses a published model.

All arithmetic uses decimal minutes and kilometres internally. Miles are converted with exactly1 mile = 1.609344 kilometres. Hours, minutes, and seconds are combined into decimal minutes before division or multiplication. The calculator retains full precision throughout those steps. Conversion and rounding happen only when a value is displayed.

Calculate pace from distance and time

Select “Pace and speed,” enter a distance, and enter the elapsed time. A 5 km distance completed in 25:00 gives 25 ÷ 5 = 5 decimal minutes per kilometre. The displayed result is 5:00 /km. Multiplying that unrounded pace by 1.609344 gives the equivalent 8:03 /mi. The reciprocal speed is12.00 km/h, equivalent to 7.46 mph.

Pace is displayed as minutes and zero-padded seconds, rounded to the nearest whole second. Speed is displayed to two decimal places. The pace and speed panels always show metric and imperial results together, regardless of the input unit. This makes the page useful as a running pace calculator and as a direct converter without requiring a unit toggle after each calculation.

For swimming, pace is usually counted per 100 m or per 100 yd instead, and the swim pace calculator works in those units.

Calculate finish time from distance and pace

Select “Finish time” when distance and pace are known. The calculator converts both to kilometres and decimal minutes per kilometre, then multiplies them. Ten miles at 7:30 per mile produces 75 decimal minutes, displayed as 1:15:00. Time is shown as hours, minutes, and seconds when it reaches one hour, and as minutes and seconds for shorter results.

The 5K, 10K, half-marathon, and marathon presets enter their defined metric distances. The half marathon uses exactly 21.0975 km, and the marathon uses exactly 42.195 km. Those constants are not shortened to 21.1 or 42.2 during calculation. At an entered pace, the finish-time result is simple multiplication across that exact distance.

Calculate distance from time and pace

Select “Distance” when elapsed time and pace are known. Forty-five minutes at 9:00 per mile gives5.00 mi, equivalent to 8.05 km after display rounding. Internally, the kilometre result remains unrounded. This direction uses time divided by pace and does not infer anything about the activity beyond the values entered.

A distance result is displayed to two decimal places in both units. If the selected display unit is miles, miles appear as the main answer; if kilometres are selected, kilometres appear first. The pace and speed conversions remain visible underneath so all four unit expressions can be read from one result.

Marathon pace calculator: finish time and pace from distance

Use this page as a marathon pace calculator by selecting the existing mode that matches the value you need. For “Finish time,” choose the marathon preset at exactly 42.195 km or the half-marathon preset at exactly 21.0975 km, then enter a pace to calculate the corresponding finish time. For pace, select “Pace and speed,” choose or enter the marathon or half-marathon distance, and supply a finish time. The result shows the required pace per kilometre and per mile. For “Distance,” enter a time and pace to calculate how far those values cover.

These three directions answer a question for any single finish time, and the marathon and half marathon pace chart below lists common goal times with the pace per mile and per kilometre. The pace chart and the three calculator modes are definitional arithmetic and do not predict performance at a different distance. The race time predictor does that separately with the Riegel formula, as an estimate; VDOT is not used. Metric and imperial results use the same exact race distances, with 1 mile = 1.609344 kilometres, before the displayed values are rounded.

Marathon split calculator: even-pace splits

The split calculator below turns one finish time into checkpoint times at an even pace. Each split is the finish time multiplied by the checkpoint distance divided by the race distance, so the 5K split in a 4:00:00 marathon is 4:00:00 × (5 ÷ 42.195) = 28:26. The same rule gives 56:53 at 10K, 2:00:00 at halfway, 2:50:38 at 30K and 3:03:05 at 20 miles. Choose Half marathon to use it as a half marathon split calculator over exactly 21.0975 km. Splits are calculated unrounded and rounded to the nearest second only for display, so subtracting one displayed split from another by hand can be a second off.

A negative split means the second half is faster than the first. The calculator does not suggest an amount. If you enter one, as seconds (120) or as minutes and seconds (2:00), the first half is (finish time + amount) ÷ 2 and the second half is (finish time − amount) ÷ 2, so the finish time does not change. A 4:00:00 marathon with a 2:00 negative split is 2:01:00 for the first half and1:59:00 for the second. Leave the field blank for two equal halves. The checkpoint table always shows even pace.

Marathon and half marathon pace chart

Find a round goal finish time in the marathon pace chart and read the even pace per mile and per kilometre for exactly 42.195 km (26.2188 mi). The half marathon pace chart does the same for exactly 21.0975 km (13.1094 mi), which is how to use this page as a half marathon pace calculator. The “same even pace” columns multiply that pace by the other race distance, and those columns are arithmetic, not predictions.

The “same even pace” columns are arithmetic, not predictions.

Race time predictor: how the Riegel formula works

The race time predictor estimates a finish time at another distance. Predicted time equals the entered time multiplied by the ratio of the two distances, raised to 1.06: T2 = T1 × (D2 ÷ D1)^1.06, where T is minutes and D is kilometres. It accepts a finish time from 3:30 to 3:50:00 and a distance from 1.5 km to 42.2 km. A 10K finished in 50:00 estimates a half marathon of 1:50:19.

Estimate. The prediction assumes you have prepared specifically for the target distance. Accuracy drops as the gap between distances grows, and a 5K to marathon estimate is the least reliable. Riegel's 1981 paper found exponents of about 1.05 to 1.08 for runners, so 1.06 is a typical value, not a personal one. When the result carries the label “Outside the time range Riegel's paper tested — rough estimate”, the finish time is still shown because the unrounded prediction falls outside 3.5 to 230 minutes.

The 1.06 exponent is the value from Riegel's 1977 Runner's World article (Riegel PS. Time predicting. Runner's World. 1977;12(8)), which Riegel's 1981 paper cites. The 1981 paper gives the endurance equation and the 3.5 to 230 minute range: Riegel PS. Athletic records and human endurance. American Scientist. 1981;69(3):285–290.

To predict a finish time at one distance you choose, with its pace and a table for the 5K, 10K, half marathon, and marathon, use the standalone race time predictor.

Race-distance examples and exact conversions

A marathon completed in 4:00:00 produces about 5:41 /km and9:09 /mi. A half marathon completed in 1:45:00 produces about4:59 /km and 8:01 /mi. Each displayed pace is rounded only after elapsed time has been divided by the exact race distance. This avoids carrying a shortened distance into the intermediate calculation.

The pace calculator describes pace and speed only. For a separate estimate of energy associated with an activity and duration, use the calories burned calculator. For an estimate of aerobic capacity from a field test or heart-rate ratio, use theVO2 max calculator. Neither value is inserted into the pace arithmetic. To convert a known step count and pace into distance, use thesteps to miles calculator.

Inputs, rounding, and soft warnings

The time fields accept hours, minutes, and seconds; minute and second components must each remain below 60. Pace uses separate minute and second fields, with seconds below 60. Blank, non-numeric, zero, or negative quantities show a mode-specific inline prompt instead of producing a result. Because two quantities are required, the prompt identifies the visible pair needed for pace, finish time, or distance and the old result is hidden until both are valid.

Unusually fast or slow pace, distance above 500 km or 310 miles, and time above 48 hours produce a soft check-value warning. The warning does not change or block valid arithmetic. It exists to catch a likely unit selection or entry mistake. Neither the pace calculator nor the race time predictor adjusts for terrain, elevation, changing effort, or conditions.

Frequently asked questions