I read that a fighter jet hit 1500 mph in a test. How fast is that in Mach?

1500 × 0.001313703 = Mach 1.971. That's just under Mach 2, placing it in the same performance class as the F-15 Eagle (top speed ~Mach 2.5) and the old F-4 Phantom (Mach 2.23).

A hurricane is rated at 150 mph sustained winds. What fraction of the speed of sound is that?

150 × 0.001313703 = Mach 0.197. Less than one-fifth of the speed of sound — sound still travels through the storm easily, which is why you can hear thunder from distant lightning during hurricanes. For knot conversions, see [mph to knots](/speed/mph-to-knots/).

The Space Shuttle re-entered at about 17,000 mph. What Mach number is that?

17,000 × 0.001313703 = Mach 22.3. That's deep hypersonic territory (Mach 5+ is hypersonic), explaining why re-entry generates plasma temperatures exceeding 1600°C on the heat shield.

At what mph does an aircraft go supersonic?

At sea level and 20°C, Mach 1 = approximately 767 mph. Exceeding 767 mph at sea level means supersonic flight. At 35,000 ft cruise altitude, the speed of sound drops to about 660 mph, so the supersonic threshold is lower in true airspeed terms.

Mile per Hour to Mach (at sea level) Converter

Enter a value to instantly convert between speed units.

From

Precision4 dp

1 Mile per Hour = 0.0013 Mach (at sea level)

Key Formulas

Kilometer per Hour → Mile per Hour

mph = km/h × 0.621371

Mile per Hour → Kilometer per Hour

km/h = mph × 1.60934

Knot → Mile per Hour

mph = kn × 1.15078

Mile per Hour → Knot

kn = mph × 0.868976

Formula

Ma = mph × 0.001313703

Miles per hour is the everyday speed unit in the US and UK, but aviation and aerospace use Mach numbers to describe performance relative to the speed of sound. When reading American aviation news, comparing fighter jet specs, or converting a hurricane's wind speed in mph to see how it relates to sonic speed, the mph-to-Mach conversion is the bridge. Mach 1 equals approximately 767 mph at sea level and 20°C.

Source: ICAO International Standard Atmosphere, 1976

Frequently Asked Questions

Real-World Examples

Speed of sound at sea level and 20°C — 767 mph is Mach 1.0, the sonic barrier. Often rounded to 768 mph in US aviation texts.

767 mph = 1 Ma

Approximate top speed of an F-22 Raptor — just over Mach 2, achieved in supercruise with afterburners at altitude.

1550 mph = 2.036 Ma

Concorde's record speed over the North Atlantic — about Mach 2.02 at cruise altitude (where sound speed is lower), here expressed as sea-level Mach equivalent.

2193 mph = 2.881 Ma

Top speed of a fast propeller aircraft like a Cessna Citation — Mach 0.26, well in the subsonic regime with no compressibility concerns.

200 mph = 0.263 Ma

kmh to mph mph to kmh knots to mph mph to knots ms to kmh kmh to ms

Mile per Hour to Mach (at sea level) Converter

Key Formulas

Formula

Frequently Asked Questions

Real-World Examples

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