Mach to km/h Converter
Convert Mach number to kilometers per hour — at sea level Mach 1 is about 1,225 km/h. Results update as you type; exact factors shown.
One Mach (sea level, 15 °C) is 1,225.044 kilometer per hour — see the exact factor, not a rounded rule of thumb.
How the mach to km/h converter works
Speeds convert through meters per second. 1 km/h is 1000/3600 m/s; 1 mph is 1609.344/3600 m/s; a knot is one nautical mile (1,852 m) per hour. Mach is shown against the standard sea-level speed of sound of 340.29 m/s and varies with altitude and temperature.
The US uses customary units (US gallon, short ton, °F) in daily life; NIST SP 811 gives the exact SI factors.
Common speed conversions
| From | To | Units |
|---|---|---|
| 0.5 Ma | 612.522 km/h | Mach (sea level, 15 °C) to kilometer per hour |
| 0.8 Ma | 980.0352 km/h | Mach (sea level, 15 °C) to kilometer per hour |
| 0.85 Ma | 1,041.2874 km/h | Mach (sea level, 15 °C) to kilometer per hour |
| 0.9 Ma | 1,102.5396 km/h | Mach (sea level, 15 °C) to kilometer per hour |
| 1 Ma | 1,225.044 km/h | Mach (sea level, 15 °C) to kilometer per hour |
| 1.5 Ma | 1,837.566 km/h | Mach (sea level, 15 °C) to kilometer per hour |
| 2 Ma | 2,450.088 km/h | Mach (sea level, 15 °C) to kilometer per hour |
| 2.5 Ma | 3,062.61 km/h | Mach (sea level, 15 °C) to kilometer per hour |
| 3 Ma | 3,675.132 km/h | Mach (sea level, 15 °C) to kilometer per hour |
| 5 Ma | 6,125.22 km/h | Mach (sea level, 15 °C) to kilometer per hour |
| 8 Ma | 9,800.352 km/h | Mach (sea level, 15 °C) to kilometer per hour |
| 10 Ma | 12,250.44 km/h | Mach (sea level, 15 °C) to kilometer per hour |
Units in this converter and their exact factors
| Unit | Symbol | One unit in meter per seconds |
|---|---|---|
| meter per second | m/s | 1 meter per second |
| kilometer per hour | km/h | 0.2777777778 meter per second |
| mile per hour | mph | 0.44704 meter per second |
| knot | kn | 0.5144444444 meter per second |
| foot per second | ft/s | 0.3048 meter per second |
| Mach (sea level, 15 °C) | Ma | 340.29 meter per second |
FAQFrequently asked questions about speed conversion
What is Mach 1 in km/h?
About 1,225 km/h at sea level in standard conditions.
Does Mach 1 change with altitude?
Yes. The speed of sound falls with temperature, so Mach 1 at cruising altitude is nearer 1,060 km/h. This page uses the sea-level value.
What is a typical airliner cruise speed?
About Mach 0.85, roughly 900 km/h at altitude.
What is Mach 2?
Twice the speed of sound — Concorde cruised at about Mach 2.02.
What is hypersonic?
Mach 5 and above.
Where these figures come from
- BIPM — The International System of Units (SI Brochure, 9th edition) — definitions of the base and derived units.
- NIST Special Publication 811 — Guide for the Use of the International System of Units — the exact conversion factors used here.
- National Institute of Standards and Technology (NIST) — United States's national measurement authority.
Last checked: September 2026. Conversion factors are fixed by definition and do not change with tax years or regulations.