Mach 1
1,235 km/hSpeed · definition
Mach depends on sound speed. Here Mach 1 is 343 m/s in dry air at 20 °C.
Speed
Just how fast is Mach 1?
Air & orbit
Mach 1
DISTANCE IN ONE SECOND
Mach 1
Mach depends on sound speed.
1,235 km/hSpeed
0
343 m in 1 s
Sound in air
Sound in air is the propagation of pressure waves through the atmosphere, which can be heard by humans and animals.
1,235 km/hSpeed
0
343 m in 1 s
Each track shows distance covered in the same second. The small illustrations identify the movers; their sizes are schematic.
A little perspective
Mach 1 is approximately equal to the speed of sound in air.
Measurements, assumptions & sources +
Mach 1
Speed: 1,235 km/h; definition.
Mach depends on sound speed. Here Mach 1 is 343 m/s in dry air at 20 °C.
Sound in air
Speed: 1,235 km/h; approximate.
Approximately 343 m/s in dry air at 20 °C. Mach numbers use this stated local sound speed.
The marked speed is calibrated. Unmeasured illustration details are representative.
Measurement details
Why these numbers?
Compare Mach 1 with the speed of sound in air. The notes below explain how each value was chosen.
Sound in air
1,235 km/hSpeed · approximate
Approximately 343 m/s in dry air at 20 °C. Mach numbers use this stated local sound speed.
- Comparing
- Speed ↔ Speed
- Relative size
- Mach 1 is approximately equal to the speed of sound in air.
How to read the visual
The diagram uses the recorded measurements. Details outside the marked spans do not set the scale.
- The speed of sound in air: This is an estimate; check the notes for its rounding and uncertainty.
Speed is distance per unit time; it does not specify the total distance travelled.
343 m/smetres per second
1,234.8 km/hkilometres per hour
767.27 mphmiles per hour
0.00011441% of c (1.1441 × 10⁻⁶c)speed of light
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