This acceleration converter changes an acceleration between meters per second squared, standard gravity (g), feet per second squared, gal (cm/s²) and related units. Formula: m/s² = g × 9.80665; m/s² = ft/s² × 0.3048. All values go through m/s², the SI unit. Standard gravity is defined as exactly 9.80665 m/s², and 1 ft/s² is exactly 0.3048 m/s².
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How to use the acceleration converter
- Enter the acceleration, for example 3 from an accelerometer reading in g.
- In the acceleration converter, choose its unit and the target unit, such as g to m/s².
- Read the acceleration converter result: 3 g = 29.42 m/s².
For m/s² to g, divide by 9.80665. The g here is the conventional standard value; actual gravity varies slightly with latitude and altitude.
What is acceleration?
Acceleration is the rate at which velocity changes. The SI unit is the meter per second squared (m/s²). Standard gravity, g, is defined as exactly 9.80665 m/s², and the gal (1 cm/s²) is used in geophysics.
Conversion formula
Every unit is stored as a multiple of the base unit, the meter per second squared (m/s²). To convert:
value in target unit = value × (factor of source unit ÷ factor of target unit)
where each factor is the size of the unit in meters per second squared.
Common acceleration conversions
| From | To | 1 unit equals |
|---|---|---|
| standard gravity (g₀) | meter per second squared (m/s²) | 9.80665 m/s² |
| meter per second squared (m/s²) | foot per second squared (ft/s²) | 3.28084 ft/s² |
| gal (Gal) | meter per second squared (m/s²) | 0.01 m/s² |
| kilometer per hour per second (km/h/s) | meter per second squared (m/s²) | 0.2777778 m/s² |
Acceleration converter worked example
Convert 25 standard gravities to meters per second squared:
- Factor of g₀ = 9.80665 m/s²
- Factor of m/s² = 1 m/s²
- 25 × 9.80665 ÷ 1 = 245.1662 m/s²
Acceleration unit reference
| Unit | Symbol | Group | Equals (m/s²) |
|---|---|---|---|
| Meter per Second Squared | m/s² | SI | 1 |
| Standard Gravity | g₀ | Common | 9.80665 |
| Gal | Gal | CGS | 0.01 |
| Foot per Second Squared | ft/s² | US/Imperial | 0.3048 |
| Inch per Second Squared | in/s² | US/Imperial | 0.0254 |
| Kilometer per Hour per Second | km/h/s | Automotive | 0.2777777778 |
| Mile per Hour per Second | mi/h/s | Automotive | 0.44704 |
Reverse factors for each acceleration unit
The reference table gives each unit in meter per second squareds. To go the other way, divide by that factor; the list below does the division for you.
- Standard Gravity (g₀), Common: 1 g₀ = 9.80665 m/s², so 1 m/s² = 0.1019716 g₀.
- Gal (Gal), CGS: 1 Gal = 0.01 m/s², so 1 m/s² = 100 Gal.
- Foot per Second Squared (ft/s²), US/Imperial: 1 ft/s² = 0.3048 m/s², so 1 m/s² = 3.28084 ft/s².
- Inch per Second Squared (in/s²), US/Imperial: 1 in/s² = 0.0254 m/s², so 1 m/s² = 39.37008 in/s².
- Kilometer per Hour per Second (km/h/s), Automotive: 1 km/h/s = 0.2777778 m/s², so 1 m/s² = 3.6 km/h/s.
- Mile per Hour per Second (mi/h/s), Automotive: 1 mi/h/s = 0.44704 m/s², so 1 m/s² = 2.236936 mi/h/s.
0–60 mph times as average acceleration
A 0–60 mph time can be turned into average acceleration: 60 mph is exactly 26.8224 m/s, so divide that by the time in seconds:
| 0–60 mph time | Average acceleration (m/s²) | In g |
|---|---|---|
| 3 s | 8.94 | 0.912 |
| 4 s | 6.71 | 0.684 |
| 5 s | 5.36 | 0.547 |
| 6 s | 4.47 | 0.456 |
| 8 s | 3.35 | 0.342 |
| 10 s | 2.68 | 0.274 |
| 12 s | 2.24 | 0.228 |
A 3-second car averages close to 0.9 g. Real launches are not uniform, so peak values are higher.
Apparent weight in multiples of g
“g force” expresses acceleration as a multiple of standard gravity. At 2 g, a 70 kg person presses on the seat with about 1,373 N (70 × 2 × 9.80665), twice their normal weight. For force units, use the force converter. Ft/s² to m/s² is multiply by 0.3048; standard gravity is about 32.174 ft/s².
Braking and everyday acceleration
Deceleration uses the same units as acceleration, with a minus sign or the word braking. A car that stops from 100 km/h (27.78 m/s) in 3.5 seconds decelerates at about 7.94 m/s². The acceleration converter shows that as about 0.81 g, which is a hard stop on dry pavement. Normal braking is closer to 0.3 g.
Other reference values: a passenger lift starts at around 1 m/s², or about 0.1 g; a commercial jet on takeoff reaches roughly 0.3 g; and an object in free fall near the Earth’s surface accelerates at 9.80665 m/s², exactly 1 g by definition. If an acceleration converter result for a car or lift is many times higher than these, check whether the input was in ft/s² rather than m/s².
Related converters and calculators
Related motion tools:
- Speed converter: mph, km/h, m/s
- Force converter: N and lbf
- Angular acceleration units: rad/s² and rpm/s
- Angular velocity converter: rpm and rad/s
- Speed calculator: distance and time
Sources
NIST Special Publication 811, Appendix B; BIPM: SI Brochure.
Questions about this calculator
What is the SI unit of acceleration?
Meters per second squared (m/s²).
How do I convert g to m/s²?
Multiply by 9.80665. For example, 4 g = 39.23 m/s².
How do I convert m/s² to g?
Divide by 9.80665. For example, 15 m/s² = 1.53 g.
How do I convert ft/s² to m/s²?
Multiply by 0.3048 (exact). For example, 32.174 ft/s² = 9.807 m/s².
Is standard gravity the same everywhere?
No. 9.80665 m/s² is a defined conventional value. Measured gravity at the surface ranges from about 9.78 m/s² at the equator to about 9.83 m/s² at the poles.
What is a gal?
The gal (Gal) is a CGS unit equal to 1 cm/s², or 0.01 m/s². It is used in geodesy and gravimetry.
Check the assumptions and units before relying on a result. Financial, tax and health estimates do not replace advice for your individual circumstances.
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