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Pace Converter

Converts a running pace or speed given in any one of min/km, min/mile, km/h or mph into all four units, plus seconds per km/mile and metres per second.

When to use

You need to translate a treadmill speed into a pace, a min/mile pace into min/km, or any other pace/speed unit conversion.

Do not use when: You have a distance and time rather than a pace (use running-pace) or a swim time (use swim-pace).

Formula

pace_s_per_km = 3600 / speed_kmh; pace_s_per_mile = pace_s_per_km × 1.609344; speed_mph = speed_kmh / 1.609344; speed_m_per_s = speed_kmh / 3.6 (1 mile = 1609.344 m)

Inputs

Parameter	Type	Unit	Required	Description
`pace_min_per_km`	string		no	Pace as mm:ss per kilometre (e.g. 5:00) or decimal minutes (5.5). Give exactly one of the four inputs; if several are given, this one takes precedence.
`pace_min_per_mile`	string		no	Pace as mm:ss per mile (e.g. 8:03) or decimal minutes.
`speed_kmh`	number	km/h	no	Speed in kilometres per hour (e.g. treadmill display). Range: > 0, ≤ 100
`speed_mph`	number	mph	no	Speed in miles per hour. Range: > 0, ≤ 60

Outputs

Output	Type	Unit	Description
`pace_min_per_km`	string	min:sec/km	Minutes and seconds per kilometre.
`pace_min_per_mile`	string	min:sec/mi	Minutes and seconds per mile.
`speed_kmh`	number	km/h	Kilometres per hour.
`speed_mph`	number	mph	Miles per hour.
`pace_seconds_per_km`	number	s/km	Pace as seconds per kilometre.
`pace_seconds_per_mile`	number	s/mi	Pace as seconds per mile.
`speed_m_per_s`	number	m/s	Metres per second.
`source_input`	string		Which input was used as the source value.

Example

5:00 min/km: {"pace_min_per_km":"5:00"} → {"pace_min_per_mile":"8:03","speed_kmh":12,"speed_mph":7.46,"pace_seconds_per_km":300,"pace_seconds_per_mile":482.8,"speed_m_per_s":3.333,"source_input":"pace_min_per_km"}

6 mph treadmill: {"speed_mph":6} → {"speed_kmh":9.66,"pace_min_per_mile":"10:00","pace_min_per_km":"6:13","pace_seconds_per_km":372.8}

GET https://tttkmbb.com/api/v1/calculate/pace-converter?pace_min_per_km=5%3A00

Machine access

API: GET https://tttkmbb.com/api/v1/calculate/pace-converter (query parameters) or POST with a JSON body {"inputs": {...}}
Schema: https://tttkmbb.com/api/v1/calculators/pace-converter · Markdown: https://tttkmbb.com/fitness/pace-converter.md · JSON definition: https://tttkmbb.com/fitness/pace-converter.json
MCP: server https://tttkmbb.com/mcp, tool run_calculator with calculator_id="pace-converter"
OpenAPI operationId: convert_running_pace
Freshness: static. Authentication: none. Rate limit: fair use (see rate limits).

Sources

NIST Special Publication 811 – Guide for the Use of the SI (Appendix B: 1 mile = 1609.344 m, 1 yard = 0.9144 m) (standard)

FAQ

What if I give more than one input?

The first available in the order pace_min_per_km, pace_min_per_mile, speed_kmh, speed_mph is used and the rest are ignored; a note says which one.

How do I enter a pace like 7 minutes 30 seconds?

As 7:30 or as decimal minutes 7.5; both give the same result.

Related calculators

Running Pace Calculator — Pace from a distance and time, with race splits.
Swim Pace Calculator — Pace per 100 m for swimming.
Speed Converter — General speed unit conversions.