Mach Number Calculator
Compute Mach number M = v / a and identify flow regime (subsonic, transonic, supersonic, hypersonic).
At 20°C, speed of sound ≈ 343 m/s at sea level.
How to Use This Calculator
Choose units
Select Metric (m/s) or Imperial (ft/s).
Enter object speed
Input the speed of the object or flow.
Enter speed of sound
Use known local value or an approximate standard value for your conditions.
Calculate
Press Calculate to get Mach number and regime classification.
Formula
M = v / a
Where: M is Mach number, v is object/flow speed, a is local speed of sound.
Note: a depends on medium and temperature (for air: a ≈ 331 + 0.6·T(°C) m/s near sea level).
Example: v = 250 m/s, a = 343 m/s ⇒ M = 250 / 343 = 0.729 (Subsonic)
About Mach Number Calculator
Mach number compares flow speed to the local speed of sound. It indicates compressibility effects and flow regime, which are critical in aerodynamics, turbomachinery, and high-speed vehicle design.
When to Use This Calculator
- Aircraft performance: Determine flight regime.
- Wind tunnel testing: Match similarity parameters.
- Nozzle and diffuser design: Identify compressible effects.
- High-speed vehicles: Analyze shock and drag behavior.
Why Use Our Calculator?
- ✅ Instant Results: Clear regime classification.
- ✅ Easy Inputs: Just speed and speed of sound.
- ✅ Works Anywhere: Metric and Imperial units.
Frequently Asked Questions
What is a typical speed of sound in air?
At 20°C near sea level, approximately 343 m/s (1125 ft/s). It decreases at lower temperatures and varies with medium.
Does altitude affect Mach number?
Yes. As temperature and composition change with altitude, the speed of sound changes, affecting the computed Mach number for the same true airspeed.
What are standard regime ranges?
Subsonic M < 0.8, Transonic 0.8–1.2, Supersonic 1.2–5, Hypersonic ≥ 5.
Can I compute a from temperature?
Approximate formulas exist (e.g., a ≈ 331 + 0.6·T(°C) for air near sea level). For precision, use thermodynamic relations and local conditions.