What speed of sound does this use?

343 m/s, an approximate value for dry air near 20°C (68°F) at sea level. ISA sea-level conditions at 15°C are closer to 340.3 m/s.

Does the speed of sound change with altitude or temperature?

Yes. At 30,000 ft the speed of sound drops to about 295 m/s due to lower temperature. This converter uses the sea-level standard (343 m/s), which is the most common reference point for Mach number definitions.

Mach 1 is the local speed of sound. With this tool's 343 m/s reference it is about 1,235 km/h or 767 mph; the real value changes with air temperature.

Can I enter decimal Mach numbers?

Yes. Values like Mach 0.85 (typical cruising speed of commercial jets) or Mach 2.5 are fully supported. The result updates as you type.

How do I convert back from m/s to Mach?

Divide your m/s value by 343. For example, 686 m/s ÷ 343 = Mach 2. Use our Meter per Second to Mach converter for that direction.

Mach to Meters per Second Converter

Enter a Mach number and instantly get the equivalent speed in meters per second, km/h, and mph.

Enter Mach Number

Speed of sound reference: 343 m/s (sea level, approximately 20°C)

Mach Number

Common Presets

Results

Enter a Mach number to see results.

Mach Speed Reference Table

Standard sea-level values (343 m/s reference)

Mach	m/s	km/h	mph	Classification

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Summary

This converter turns any Mach number into meters per second using the standard speed of sound at sea level (343 m/s). It also shows the equivalent speed in km/h and mph, making it easy to cross-reference across unit systems used in aviation, physics, and engineering.

How it works

Enter a Mach number in the input field (e.g. 1, 2.5, 0.85).
The converter multiplies by an approximate 343 m/s sea-level reference for dry air near 20°C.
Results appear instantly in m/s, km/h, and mph.
Use the common presets (Mach 1–5) for quick reference.
Click "Copy" next to any result to copy that value to your clipboard.

Use cases

Convert fighter jet or missile speeds from Mach to metric units.
Understand supersonic and hypersonic speed classifications.
Calculate m/s for physics or engineering coursework.
Compare aircraft speeds during aviation study or research.
Estimate travel time for supersonic vehicles at a given Mach number.
Cross-check wind tunnel or CFD simulation speed parameters.

Frequently Asked Questions

Last updated: 2026-06-18 · Reviewed by Nham Vu