Convert Meters per Second to Mach - Speed Converter

This converter translates a speed given in meters per second (m/s) into a Mach number (ratio of object speed to local speed of sound). Mach number is dimensionless and commonly used in aeronautics, acoustics, and fluid dynamics to classify subsonic, transonic, supersonic, and hypersonic regimes.

Because the local speed of sound depends on the thermodynamic state of the medium (principally temperature for gases), a single numeric conversion requires an assumption about atmospheric conditions. This tool uses a standard reference for air unless otherwise stated in the methodology and provides guidance on accuracy and when to use measured local speed of sound instead.

Updated Nov 17, 2025QA PASS — golden 25 / edge 120Run golden-edge-2026-01-23

Governance

Record d85b4e4e4f8b • Reviewed by Fidamen Standards Committee

Interactive Converter

Convert between meter per second and mach with precision rounding.

Meter per Second (m/s)Mach (M)

Quick reference table

Meter per Second	Mach
1 m/s	0.0105 M
5 m/s	0.0525 M
10 m/s	0.105 M
25 m/s	0.2624 M
50 m/s	0.5248 M
100 m/s	1.0496 M

Methodology

Primary relationship: Mach number M is defined as M = v / a where v is object speed and a is the local speed of sound in the same medium and direction.

For dry air under typical engineering assumptions, the speed of sound is estimated from the ideal-gas relation a = sqrt(gamma * R_specific * T), where gamma is the ratio of specific heats, R_specific is the specific gas constant for air, and T is absolute temperature (Kelvin). This converter assumes gamma = 1.4 and R_specific = 287.058 J/(kg·K) unless a different reference is specified in accompanying documentation.

A standard reference temperature commonly used for conversions is 15 °C (288.15 K). At that temperature the speed of sound in air is approximately 340.294 m/s, so 340.294 m/s corresponds to Mach 1 under those reference conditions. For precise or regulatory work, use measured local temperature and humidity or direct measurement of speed of sound; references to NIST and ISO standards are provided below.

Key takeaways

This converter computes Mach as the ratio of input speed to an assumed local speed of sound. Default reference uses standard air at 15 °C (a ≈ 340.294 m/s).

For engineering, safety, or regulatory purposes, replace the default with measured local conditions and document assumptions and uncertainties in accordance with NIST and applicable ISO/IEEE guidance.

Worked examples

Example 1: 170.147 m/s with default reference speed of sound 340.294 m/s → Mach = 170.147 / 340.294 ≈ 0.5.

Example 2: 340.294 m/s at reference conditions → Mach = 340.294 / 340.294 = 1.0.

Example 3: 1020.882 m/s at reference conditions → Mach = 1020.882 / 340.294 ≈ 3.0.

F.A.Q.

Does Mach depend on temperature and altitude?

Yes. The local speed of sound depends primarily on temperature (and to a lesser extent on composition and humidity). Altitude affects temperature and pressure through the atmosphere profile, so Mach for a given m/s value will change with altitude. Use local thermodynamic data for accurate results.

Can I use this conversion for gases other than air?

The standard assumptions and numeric reference (gamma = 1.4, R = 287.058 J/(kg·K)) apply to dry air. For other gases, use the appropriate specific heat ratio and gas constant or measure the speed of sound directly before converting.

How accurate is the conversion?

Using the standard reference (15 °C, dry air) gives typical engineering accuracy for many applications, but not for high-precision metrology or regulatory compliance. Uncertainty arises from temperature variability, humidity, and non-ideal gas effects. For precision work, measure or calculate the local speed of sound using traceable sensors and follow NIST and ISO guidance.

Is Mach calculated from true airspeed or indicated/ground speed?

Mach is defined using the speed relative to the local air (true airspeed for aircraft). Ground speed differs from true airspeed when there is wind. For aerodynamic/regulatory use, convert true airspeed to Mach using local speed of sound.

Are there operational limits where this conversion is not appropriate?

Yes. In transonic and supersonic regimes compressibility effects, shock formation, and non-equilibrium thermodynamics mean local flow properties can differ significantly from free-stream approximations. For high-Mach applications consult aerodynamic specialists and relevant standards before using a simple conversion.

How should I report converted values for engineering or regulatory documents?

Report the input speed, the assumed or measured local speed of sound (including temperature and humidity or reference condition), the computed Mach value, and an uncertainty estimate. Cite applicable standards such as NIST and ISO where measurement traceability is required.

Sources & citations

NIST — Reference on Constants, Units, and Uncertainty — https://www.nist.gov
ISO — Standard atmosphere and related measurement practices (see ISO standards catalogue) — https://www.iso.org
IEEE — Recommended practices for measurement and reporting in instrumentation and controls — https://standards.ieee.org
OSHA — Guidance on measurement practices and workplace safety for compressed gases and high-speed machinery — https://www.osha.gov
ISO 80000-3:2019 — Space and time — https://www.iso.org/standard/64974.html
NIST SP 811 — Guide for the Use of the International System of Units — https://www.nist.gov/pml/special-publication-811

Further resources

Related tools

External guidance

Versioning & Change Control

Audit record (versions, QA runs, reviewer sign-off, and evidence).

Record ID: d85b4e4e4f8b

What changed (latest)

v1.0.0 • 2025-11-17 • MINOR

Initial publication and governance baseline.

Why: Published with reviewed formulas, unit definitions, and UX controls.

Public QA status

PASS — golden 25 + edge 120

Last run: 2026-01-23 • Run: golden-edge-2026-01-23

Engine

v1.0.0

Data

Baseline (no external datasets)

Content

v1.0.0

Governance

Last updated: Nov 17, 2025

Reviewed by: Fidamen Standards Committee (Review board)

Credentials: Internal QA

Risk level: low

Reviewer profile (entity)

Fidamen Standards Committee

Review board

Internal QA

Entity ID: https://fidamen.com/reviewers/fidamen-standards-committee#person

Semantic versioning

MAJOR: Calculation outputs can change for the same inputs (formula, rounding policy, assumptions).
MINOR: New features or fields that do not change existing outputs for the same inputs.
PATCH: Bug fixes, copy edits, or accessibility changes that do not change intended outputs except for previously incorrect cases.

Review protocol

Verify formulas and unit definitions against primary standards or datasets.
Run golden-case regression suite and edge-case suite.
Record reviewer sign-off with credentials and scope.
Document assumptions, limitations, and jurisdiction applicability.

Assumptions & limitations

Uses exact unit definitions from the Fidamen conversion library.
Internal calculations use double precision; display rounding follows the unit's configured decimal places.
Not a substitute for calibrated instruments in regulated contexts.
Jurisdiction-specific rules may require official guidance.

Change log

v1.0.0 • 2025-11-17 • MINOR

Initial publication and governance baseline.

Why: Published with reviewed formulas, unit definitions, and UX controls.

Areas: engine, content, ui • Reviewer: Fidamen Standards Committee • Entry ID: 8a60fd0534f2