Acceleration Unit Converter

Convert between m/s², g (Earth g), ft/s², in/s², Gal, mGal, µGal, km/h/s, mph/s, and knot/s. Private by design—everything runs locally in your browser.

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About Acceleration Units & Conversions

Acceleration measures the rate of change of velocity. In physics and engineering, you’ll most often see it in metres per second squared (m/s²), the SI unit. Some fields, however, prefer convenient alternatives such as standard gravity (g) for human-centric loads, Gal for geophysics, or everyday transport units like km/h/s and mph/s. This converter lets you move between them instantly and precisely.

  • m/s² (SI) — Base unit. One m/s² means velocity increases by 1 metre per second every second.
  • g (standard gravity) — Defined constant for Earth’s gravity at sea level: 1 g = 9.80665 m/s². Useful for acceleration loads on people, vehicles, and electronics.
  • ft/s² — Imperial/US customary analogue: 1 ft/s² = 0.3048 m/s²; equivalently 1 m/s² ≈ 3.28084 ft/s².
  • in/s² — Finer imperial unit: 1 in/s² = 0.0254 m/s²; 1 m/s² ≈ 39.3701 in/s².
  • Gal (Galileo) — Geophysics & gravimetry: 1 Gal = 1 cm/s² = 0.01 m/s². Submultiples: mGal = 1×10⁻⁵ m/s², µGal = 1×10⁻⁸ m/s² (micro-gals measure tiny gravity changes).
  • km/h/s — Transport & rail: change in kilometres per hour every second. 1 km/h/s = (1000/3600) m/s² ≈ 0.27778 m/s².
  • mph/s — Automotive & aviation legacy: 1 mph/s = 1609.344/3600 m/s² ≈ 0.44704 m/s².
  • knot/s — Maritime & aviation: 1 kt/s = 1852/3600 m/s² ≈ 0.51444 m/s².

How to Convert

The simplest approach is to convert your input to m/s², then to the target unit. For example, to convert 3 m/s² into g, divide by standard gravity: 3 / 9.80665 ≈ 0.305 g. To go the other way, multiply: 0.305 g × 9.80665 ≈ 3.00 m/s².

Typical Use Cases

  • Human tolerance — Rollercoasters and rockets quote peak loads in g.
  • Geophysics — Gravity anomalies and tidal effects are reported in mGal or µGal.
  • Transport — Trains, cars, and ships often list throttle/braking as km/h/s, mph/s, or knot/s.

Precision & Formatting

This tool supports fixed and scientific notation with adjustable digits. For very small signals (e.g., µGal-level), select scientific notation to avoid rounding away meaningful detail. All calculations run locally in your browser for privacy; you can copy any row or share a deep link with your chosen inputs and formatting.

5 Fun Facts about Acceleration

Rollercoaster launch math

Kingda Ka hurls riders from 0 to 128 mph in 3.5 seconds—about 16.3 m/s², or 1.66 g. Your body briefly “weighs” two-thirds more than normal.

Coaster rush

µGal whisper detection

Volcano teams watch for 5 µGal bumps—just 5×10⁻⁸ m/s², roughly one two-hundred-millionth of g—to spot magma creeping upward.

Gravity sleuths

Hummingbird dive pulls

Male Anna’s hummingbirds hit 10 g during courtship dives, equal to 98 m/s² or a dizzying 219 mph each second.

Wildlife physics

Ion thrusters take the long view

NASA’s Dawn probe accelerated at only 0.00026 m/s² (2.7×10⁻⁵ g), yet months of thrust added over 10 km/s of speed—patience beats brute force.

Space stamina

F1 braking is -5 g

A Formula 1 driver stomping the brakes experiences about -49 m/s², shedding nearly 110 mph every second—that’s tougher on the neck than some rocket launches.

Track extremes

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