speed unit converter
Convert Speed units, compare 11 unit definitions and explore formulas, examples and common questions.
Speed converter
Popular conversions
Complete unit directory11 units
Choose a source unit to see every available target unit. Each directory has a stable address.
- Kilometres per hourkm/h
- Kilometres per secondkm/s
- Knotsknot
- Metres per secondm/s
- Millimetres per secondmm/s
- Miles per hourmph
- Micrometres per secondµm/s
- Speed of light
- Feet per second
- Miles per second
- Speed of sound
No matching units. Try a name or symbol.
How to use this calculator
- Enter the value you want to convert.
- Choose the source and target units, then adjust the display precision if needed.
- Read the result. Select Convert to open a page for this value, or use the table below.
Definitions and assumptions
Speed factors are expressed relative to metres per second. The knot is one nautical mile per hour. The speed-of-sound example uses 343 m/s for dry air near 20°C; actual sound speed varies with conditions.
Frequently asked questions
Which Speed units are supported?
The directory lists 11 units, including symbols and availability. Choose any source unit to browse its target units.
how to convert mph to km/h?
The calculator converts the input to the category's reference unit, then divides by the target unit's factor. 60 × 1.609344 ≈ 96.56064 Kilometres per hour. Use the source and target factors shown in the formula. The worked example uses the value on this page, and the table provides other common values.
Is the speed of sound a fixed conversion factor?
No. The example factor is 343 m/s for dry air near 20°C. Temperature and the medium affect the actual speed of sound.
Why is the displayed result rounded?
Auto mode preserves significant digits for small values; manual mode rounds to the selected decimal places. ≈ means approximate; < means below the display limit. Extreme values use × 10ⁿ. Calculations are rounded only for display.
What input range can I use?
This calculator accepts non-negative values up to 1 trillion, with up to 8 decimal places. It does not calculate signed vectors or calendar date intervals.
Why is a unit unavailable?
A conversion is unavailable when a verified unit definition or a current exchange-rate value has not been configured. The tool does not invent a coefficient.
Sources and methodology
Methods and sources · Content revised
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