Calculator

Pace calculator.

Enter a distance and finish time to get your pace (per km and per mile) and speed. We’ll also show race‑distance finish times at that pace, plus examples and tips.

Calculate pace & speed

Distance (km)

Finish time (hh:mm:ss)

You can enter mm:ss (e.g., 50:00) or seconds (e.g., 3000).

Finish times at this pace

Distance	Time
1 km	—
1 mile	—
5 km	—
10 km	—
Half marathon	—
Marathon	—

How pace relates to speed and finish time

Pace is how long it takes to cover a unit distance (e.g., minutes per kilometre). Speed is the inverse (e.g., kilometres per hour). If you know any two of distance, time, and pace, you can compute the third. This tool converts between them and shows finish times for popular race distances at your calculated pace.

Worked examples

Examples rounded to the nearest second.
Scenario	Inputs	Result
10K in 50:00	Distance: 10 km; Time: 00:50:00	Pace ≈ 5:00 /km (≈ 8:03 /mi); Speed ≈ 12.0 km/h
Half marathon in 1:45:00	Distance: 21.0975 km; Time: 01:45:00	Pace ≈ 4:59 /km; Finish marathon at this pace ≈ 3:29:00
5K at 8:00 /mi	Pace: 8:00 /mi	Finish time ≈ 24:52; Pace ≈ 4:58 /km

Limitations & context

Real‑world pace varies with terrain, elevation, temperature, and fueling.
Training paces differ from race paces; use HR zones or RPE to guide easy vs. hard efforts.
Negative split strategies (faster second half) can change finish estimates.

Related tools

Interpreting your pace

Add a distance and finish time to see a personalised explanation of your pace here. We’ll also note equivalent speeds and typical training zone contexts.

Frequently asked questions

What is a good 10K pace?

It depends on age, experience, and training. Recreational runners often target 5:00–6:30 /km (8:00–10:30 /mi), but your best metric is personal improvement over time.

How do I convert between min/km and min/mile?

1 mile ≈ 1.609 km. Multiply your min/km by 1.609 to get min/mile (or divide min/mile by 1.609 to get min/km). This page calculates both automatically.

Why does treadmill pace feel different outdoors?

Wind resistance, surface, temperature, and gradient changes outdoors can make the same numeric pace feel harder. A 1% treadmill incline often approximates outdoor effort.

How accurate are predicted finish times?

They assume you can sustain the same pace across the full distance, which may not hold with fatigue, hills, or heat. Use them as planning estimates, not guarantees.

Pace & speed formula breakdown

The calculator works from the three-way relationship between distance, time, and rate. Once any two are known we solve for the third and display both metric and imperial equivalents.

Quantity	Formula used	Notes
Pace (per km)	pace_km = time ÷ distance_(km)	Returned as mm:ss by dividing seconds per km into minutes and seconds.
Pace (per mile)	pace_mi = time ÷ distance_(mi); distance is converted with 1 mile = 1.60934 km.	We derive mile distance first so that rounding differences stay under 0.1 s.
Speed (km/h)	speed_km/h = distance_(km) ÷ time_(hours)	Time in seconds is divided by 3600 to convert to hours.
Speed (mph)	speed_mph = distance_(mi) ÷ time_(hours)	Uses the same converted mile distance to keep results internally consistent.

Choosing your inputs

Distance + time (default) — plus: Works with any race or training segment, supports hh:mm:ss or raw seconds. Minus: Requires a known finish time; live pacing needs a watch split.
Known pace — plus: Enter pace directly (e.g., via quick buttons) and we infer time for any distance. Minus: Small pace entry errors propagate to all predictions.

All conversions happen at double precision and are rounded only when displayed, so copying the km pace into another tool and reconverting will match to within ±0.5 seconds.