Running Pace Calculator

What does this calculator do?

The pace calculator answers a simple question: how fast was that, per kilometre and per mile? Enter any distance and the time it took, and it returns your average pace (min/km and min/mile), your average speed (km/h and mph) and a split table with the cumulative time at each kilometre or mile marker.

Typical uses: checking the pace of a finished race or workout, working out the pace a goal finish time requires (enter the race distance and your target time), and producing split times to memorise or write on a pace band.

How does it work?

Pace and speed are two views of the same number. Pace is time divided by distance — how long one kilometre takes. Speed is distance divided by time — how far you travel in one hour. Runners usually think in pace because it maps directly onto a watch display and onto split times.

The calculator first converts your distance to kilometres (miles × 1.609344, metres ÷ 1000) and your time to seconds. Every other figure is derived from those two values, so pace, speed and splits are always consistent with each other. Values are rounded only at the very end, for display.

Formula

pace (s/km)   = time (s) ÷ distance (km)
pace (s/mile) = pace (s/km) × 1.609344
speed (km/h)  = 3600 ÷ pace (s/km)
speed (mph)   = speed (km/h) ÷ 1.609344
split n       = (pace per split) × n

1.609344 is the exact length of the international mile in kilometres (1 mile = 1,609.344 m), so the unit conversions add no error. When the distance is not a whole number of kilometres or miles, the last row of the split table is the finish line itself and shows the full finish time.

Worked example

How to interpret the result

The result is your average pace over the whole distance. It says nothing about how evenly you ran: a 25:00 5K run as 4:40 per km for the first half and 5:20 for the second has the same average as five even 5:00 kilometres.

When you use it to plan a race, treat the split table as a target for an even effort, not a rule. On a hilly course, in heat or into a headwind, the same effort produces slower kilometres; most runners do best by holding the effort steady and letting splits drift a little rather than chasing every marker. To check whether a goal time is realistic in the first place, use the race time predictor with a recent result.

Assumptions and limitations

Assumptions

• The distance you enter is the distance you actually covered.
• For the split table, pace is constant from start to finish.
• The time is elapsed time from start to finish, including any stops you want counted.

Limitations

• Paces and split times are rounded to the nearest second and speeds to two decimals, so small differences from other calculators are usually rounding.
• GPS watches usually measure a race as slightly longer than its certified distance (running wide of the tangents, signal drift), so watch pace can differ from the pace implied by the official result.
• Hills, wind, heat and altitude are not modelled — the calculator converts numbers; it does not adjust for conditions.
• Splits are linear. If you plan a negative or positive split, use the printable pace band, which supports even, negative and positive splits.
• The split table is shown for distances up to 60 km.

Methodology and sources

Method type: Exact calculation

Pace and speed are definitions, not models: this calculator is exact arithmetic using the international mile (1.609344 km). The only approximation is rounding for display.

• Methodology: Pace, speed and distance
• Methodology: Rounding and displayed precision

Sources: NIST SP 811 · World Athletics Book of Rules

Last reviewed: October 5, 2026