SpeedKilometers per Hour to Miles per Hour

Kilometers per Hour to Miles per Hour

Methodology·How We Verify

Snapshot

1 Kilometer per Hour equals 0.621371 Miles per Hour.

Reference basis: This conversion uses fixed meters-per-second-based speed definitions.
Example: For 0.5 Kilometers per Hour, the result equals 0.310686 Miles per Hour.

Interactive conversion

Converter Calculator

Decimals: 1.5 or 1,5. Fractions: 1/2. Scientific notation: 1e3. Write 1000 without grouping separators.

0.621371 Miles per Hour (mph)

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API and AI agent access

Kilometers per Hour to Miles per Hour.

Machine-readable identifiers

Conversion family: speed
Source unit: kilometer_per_hour
Target unit: mile_per_hour

Use these identifiers in the API request. Sources and model limits also apply to software clients.

Example API request and response

POST /api/v1/convert

Request

{
  "family": "speed",
  "value": 1,
  "from": "kilometer_per_hour",
  "to": "mile_per_hour"
}

Essential response

{
  "ok": true,
  "conversion": {
    "family": "speed",
    "value": 1,
    "from": "kilometer_per_hour",
    "to": "mile_per_hour",
    "result": {
      "raw": 0.6213711922373341,
      "display": "0.621371"
    },
    "canonicalPath": "/speed/kilometers-per-hour-to-miles-per-hour/"
  }
}

API, OpenAPI and WebMCP documentation

Explanation

Multiply by kilometers-to-miles ratio because both units already use the same hour denominator.

Method & Reference

Method basis: exact conversion formula shown in Snapshot.
Applied factor: 1 Kilometer per Hour = 0.621371 Miles per Hour (using fixed meters-per-second-based speed definitions).
Consistency rule: calculator output and table values use the same constants and rounding policy.

Common Conversion Values

Kilometers per Hour (km/h)	Miles per Hour (mph)
1/2	0.310686
1	0.621371
2	1.242742
5	3.106856
10	6.213712
20	12.427424
30	18.641136
60	37.282272
100	62.137119
120	74.564543

Questions & answers

Frequently Asked Questions

What is 1 kilometer per hour in miles per hour?

1 Kilometer per Hour equals 0.621371 Miles per Hour on this page.