Pace & Speed Converter

Enter as:

Use pace for a watch or race target; use speed for a treadmill or GPS average.

Running pace:

Enter mm:ss, such as 5:30, or decimal minutes, such as 5.5.

Running speed:

The converter calculates pace from the selected speed without applying grade, wind, terrain, or fatigue adjustments.

Custom distance:

Optional: use 0 or leave blank for standard distances only. Changing units preserves distance.

Split spacing:

Used only with a custom distance. Every checkpoint assumes the same pace.

Extra numeric decimals:

Show more detail in converted speeds. Clock times stay rounded to the nearest second.

Measure	Equivalent	Numeric value	Unit	Copy
Enter a valid pace or speed to see its equivalents.
{{ row.label }}	{{ row.value }}	{{ number(row.raw) }}	{{ row.unit }}

Distance	Kilometres	Miles	Steady time	Seconds	Copy
Enter a valid pace or speed to see steady-distance times.
{{ row.label }}	{{ number(row.km, 4) }}	{{ number(row.km / 1.609344, 4) }}	{{ formatClock(row.time) }}	{{ number(row.time) }}

Checkpoint	Kilometres	Miles	Steady time	Seconds	Copy
Add a custom distance in Advanced to see cumulative splits. Any spacing problem is explained beside those controls.
{{ row.label }}	{{ number(row.km, 4) }}	{{ number(row.km / 1.609344, 4) }}	{{ formatClock(row.time) }}	{{ number(row.time) }}

{{ chartError || 'Enter a valid pace or speed to draw the curve.' }}

Conversion logic

Pace to speed: speed = 60 ÷ pace in minutes per unit
Speed to pace: pace = 60 ÷ speed per hour
Unit bridge: One international mile is exactly 1.609344 kilometres.
Distance times: Elapsed time is canonical seconds per kilometre multiplied by the custom distance in kilometres.
Split checkpoints: Each cumulative checkpoint uses the same steady pace; the final checkpoint is always the exact custom distance.

Every distance time assumes the same constant speed. These are arithmetic comparisons, not predictions of race performance. Grade, wind, surface, acceleration, fatigue, stops and device error are not modeled.

For pacing profiles, planned stops or cutoffs, use the Race Finish Time Calculator.

A treadmill may show kilometres per hour while a training plan gives minutes per mile. Both describe the same motion from opposite directions: speed is distance covered per unit of time, and pace is time needed per unit of distance. A faster speed therefore produces a smaller pace number.

The distinction matters when moving among watches, treadmills, race plans, and course markers. A pace of 5:00 min/km is exactly 12 km/h. Converting the same physical speed to imperial units gives about 8:03 min/mi and 7.46 mph; the runner has not become faster or slower because the unit changed.

Pace, speed, and finish-time distinctions
Measure	Typical form	Useful for
Pace	min/km or min/mi	Watch targets, splits, and race plans
Speed	km/h, mph, or m/s	Treadmills, GPS averages, and motion comparisons
Finish time	hh:mm:ss	A fixed distance at unchanged pace

A steady-pace time assumes the same ground speed from start to finish. The distance table makes that assumption explicit: it shows how long each distance would take if that speed could be maintained, without predicting whether a runner can sustain it.

For course-specific pacing profiles, planned stops or finish cutoffs, use the Race Finish Time Calculator. A pace conversion by itself does not estimate fitness, endurance or race readiness.

How to Use This Tool:

Choose the measurement you already know; switching between pace and speed preserves the same physical speed.

Select Pace or Speed, enter the value, and choose its adjacent unit. Pace accepts mm:ss, so 5:30 means 5 minutes 30 seconds; decimal minutes such as 5.5 remain supported.
Read the automatic Current equivalence and all six unit equivalents in Conversion ledger.
Open Distance times for nine standard distances at unchanged speed.
In Advanced, optionally enter a Custom distance and Split spacing. The Split times table includes every cumulative checkpoint and the exact finish, up to 100 rows.
Use extra numeric decimals for conversion detail. Copy the equivalence, export a complete table, or inspect nearby speeds in Pace curve.

Interpreting Results:

The metric and imperial pace and speed values describe the same physical speed. Clock paces and times round to the nearest second. Numeric values retain full precision internally, with raw seconds and units available in table exports.

Common-distance times and custom checkpoints assume unchanged pace. An invalid optional distance or split setting explains which timing artifact is unavailable while keeping a valid core conversion visible. It never exports a truncated checkpoint list.

Technical Details:

Pace and speed are reciprocals once their time and distance units are aligned. The calculation uses seconds per kilometre as its central quantity, converts one international mile as exactly 1.609344 kilometres, and derives every displayed unit from that same value.

Formula Core:

For speed in kilometres per hour, dividing 3,600 seconds by speed gives seconds per kilometre. Pace entered per mile is divided by 1.609344 to obtain the equivalent seconds per kilometre.

\begin{matrix} p_{km} & = & \frac{3600}{v_{kmh}} \\ p_{mi} & = & p_{km} \times 1.609344 \\ v_{mph} & = & \frac{v_{kmh}}{1.609344} \\ T & = & D \times p_{km} \end{matrix}

p is pace in seconds per distance unit, v is speed, D is distance in kilometres, and T is elapsed seconds. Split times apply the final equation to each cumulative checkpoint, always including the finish even when the chosen spacing does not divide the course evenly.

The supported pace/speed range is the same physical domain in every input unit: 0.1 through 965.6064 km/h. This broad conversion domain preserves previously supported values; it is not a claim about human running ability. Optional distance supports up to 1,609.344 km (1,000 miles). Zero or blank omits it. Clock seconds must be below 60.

Limitations:

The conversion is deterministic, while distance times assume constant speed.

Steady calculations do not adjust for grade, wind, heat, altitude, surfaces, stops, acceleration, or fatigue.
GPS distance error, treadmill calibration, and course measurement can be larger than the displayed decimal precision.
A speed suitable for a short interval may not be sustainable over a longer distance.

Worked Examples:

Five-minute kilometre pace

A pace of 5:00 min/km equals 12.00 km/h, about 8:03 min/mi and 7.46 mph. The distance table shows 25:00 for 5 km and 50:00 for 10 km at that unchanged speed. A custom distance of 2.5 km with 1 km spacing produces checkpoints at 5:00, 10:00 and the exact finish at 12:30.

References:

Guide to the SI, Appendix B.9: Conversion factors, National Institute of Standards and Technology.