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Acceleration Converter

Converters · Added 15 August 2026

Convert acceleration between metres per second squared, g-force, imperial units and the rate-of-speed-change forms used for vehicles. One g is standard gravity, exactly 9.80665 m/s², which is the yardstick most acceleration figures are quoted against.

Result

1 m/s² in standard gravity

0.101971621 g

1 m/s² = 0.101971621 g

The same value in every unit

Metre per second squared (m/s²)
1
Centimetre per second squared (gal) (cm/s²)
100
Millimetre per second squared (mm/s²)
1,000
Kilometre per second squared (km/s²)
0.001
Kilometre per hour per second (km/h/s)
3.6
Mile per hour per second (mph/s)
2.23693629
Foot per second squared (ft/s²)
3.2808399
Inch per second squared (in/s²)
39.3700787
Standard gravity (g)
0.101971621

One g is standard gravity, defined as exactly 9.80665 m/s². It is an agreed yardstick rather than a measurement of the local gravitational field, which varies slightly with latitude and altitude.

How to use the acceleration converter

  1. 1Enter the acceleration value you have.
  2. 2Pick its unit and the one you want.
  3. 3The table shows the same acceleration in every unit at once.
  4. 4For vehicle figures, km/h per second and mph per second are usually the most intuitive.
  5. 5Swap the units to reverse the conversion.

Examples

Gravity

Input
1 g
Result
9.80665 m/s² · 32.174 ft/s²

Standard gravity is defined exactly rather than measured, so this conversion is exact.

A brisk car

Input
26.82 km/h/s
Result
7.45 m/s² · 0.76 g

This is 0–100 km/h in about 3.7 seconds, sustained.

Seismology

Input
100 cm/s² (gal)
Result
1 m/s² · 0.102 g

The gal, named after Galileo, is the standard unit for ground acceleration in earthquake measurement.

About the acceleration converter

Acceleration is a change in velocity, not a speed

Acceleration measures how quickly velocity changes, which is why its units carry a squared time: metres per second, per second. A car going from rest to 27 metres per second in ten seconds averaged 2.7 m/s². The unit looks strange until you read it aloud as a rate of a rate.

Because velocity is a vector, changing direction is acceleration even at constant speed. A car cornering at a steady 60 km/h is accelerating, which is exactly what the passengers feel pushing them sideways. This is also why an object in circular orbit is permanently accelerating despite never speeding up.

The rate-of-speed-change units in this converter — km/h per second, mph per second — are dimensionally the same thing expressed more legibly for vehicles. Saying a car gains 27 km/h every second is easier to picture than saying it accelerates at 7.5 m/s², even though they are identical.

Why standard gravity is a definition

Actual gravitational acceleration varies across the Earth's surface. It is weakest at the equator, where distance from the centre is greatest and centrifugal effect largest, and strongest near the poles — roughly 9.78 to 9.83 m/s². Altitude reduces it further, and dense rock beneath your feet increases it slightly.

That variation is a problem for any unit defined in terms of gravity, which includes kilogram-force and pound-force as well as the g used here. So standard gravity was fixed by agreement at exactly 9.80665 m/s², a value close to the average at mid-latitudes at sea level. It is a convention, not a measurement, which is why it never needs revising.

The variation is small but genuinely measurable, and gravity surveying makes a science of it. Mapping tiny local differences in gravitational acceleration — measured in milligals — reveals density variations underground, which is how oil, mineral and groundwater deposits are located from the surface without drilling.

Frequently asked questions

What does g-force actually measure?
It expresses acceleration as a multiple of standard gravity, 9.80665 m/s². It is popular because it maps directly onto felt experience: at 1 g you feel your normal weight, at 2 g you feel twice as heavy, at 0 g you feel weightless. Note that despite the name it is an acceleration, not a force — the force on a body is that acceleration multiplied by its mass, which is why the same g-force is far more punishing for a heavier object.
Why is 0–60 mph not an acceleration figure?
Because it is a duration, not a rate, and real acceleration is not constant through the run. A car accelerates hardest in the middle of the range and tails off near the top, so dividing 60 mph by the elapsed time gives an average rather than anything the car actually sustains. Converting that average into g is legitimate arithmetic but describes a car that does not exist — one accelerating perfectly evenly.
What is a gal?
One centimetre per second squared, named after Galileo and used almost exclusively in geophysics and seismology. Ground motion during an earthquake is small in ordinary units, so a unit a hundred times smaller than the m/s² keeps the numbers readable. Milligals are used in gravity surveying, where variations in local gravity reveal subsurface density differences.
How much acceleration can a person take?
It depends heavily on direction, duration and body position, and this converter changes units rather than offering any safety guidance. As orders of magnitude only: sustained vertical acceleration of a few g causes vision loss in untrained people, while very brief impacts of tens of g are survivable in a properly restrained seat. Anything involving actual human exposure limits is a matter for the relevant engineering standards and medical literature, not a unit converter.

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