How to use the acceleration converter
- Type an acceleration in the From box. Decimals (9.81) and negative numbers for deceleration both work.
- Pick the unit you have in the first menu and the unit you want in the second. The To box and the result line update as you type.
- To work backwards, type in the To box and the From box follows. Press Swap units to flip the direction.
- For car performance, use 0 to 60 mph time to g-force: enter the speed gained, its unit and the Time (seconds) to read the average g.
How the conversion works
Every unit is stored as a size in meters per second squared. The tool multiplies your number by the size of the From unit, then divides by the size of the To unit: result = value × From size ÷ To size. Standard gravity is defined as exactly 9.80665 m/s². The foot is exactly 0.3048 m, the mile 1,609.344 m and the nautical mile 1,852 m, so 1 mph/s = 0.44704 m/s², 1 km/h/s = 1/3.6 m/s² and 1 kn/s = 1852/3600 m/s². The card uses average acceleration = speed gained ÷ time. The factors match NIST Guide to the SI, Appendix B.8.
Worked example with the default values
With 1 in the From box, g as the From unit and m/s² as the To unit, the result line reads 1 g = 9.80665 m/s². The reverse line reads 1 m/s² = 0.10197162 g, and the grid shows 1 g as 32.174049 ft/s² and 35.30394 km/h/s. In the 0 to 60 card, 60 mph in 6 s gives 0.45585 g on average, which is 4.4704 m/s² or 10 mph per second.
Reference values
| Situation | Typical acceleration |
|---|---|
| Standing on Earth | 1 g, 9.80665 m/s² |
| 0 to 60 mph in 6 s (average) | 0.45585 g |
| 0 to 60 mph in 3 s (average) | 0.91171 g |
| Sustained g that greys out an untrained person | about 4 g |
| Fighter pilot limit, with g-suit | about 9 g |
Working with speeds rather than accelerations? The speed converter handles mph, km/h and knots. For what an engine delivers, see the horsepower and torque calculator, and for other quantities the unit converter.
Limits and edge cases
A g-force is an acceleration measured in multiples of standard gravity, not a force. The 0 to 60 card gives the average over the whole run: a real car accelerates hardest in low gears and less as speed builds. Time must be above zero. Letters and slashes are blocked with a hint, and anything above 1e24 is refused.
Sources: NIST Guide to the SI, Appendix B.8; FAA, Acceleration in Aviation: G-Force.
Acceleration converter FAQ
How do I convert g to m/s²?
Multiply the g-force by 9.80665. For example, 3 g × 9.80665 = 29.41995 m/s². To go back, divide m/s² by 9.80665.
What is 1 g in ft/s²?
One standard gravity is 32.174049 ft/s², or 21.936851 mph per second. That is the acceleration of a freely falling object near Earth's surface, about 32.2 ft/s².
How many g is 0 to 60 mph in 3 seconds?
About 0.91 g on average. 60 mph in 3 seconds is 20 mph per second, which is 8.9408 m/s², and dividing by 9.80665 gives 0.9117 g. Real cars pull harder in first gear than in third.
How many g can a person tolerate?
Healthy untrained people typically grey out at about 4 g and black out at about 5 g when it is sustained from head to foot. Fighter pilots reach 9 g for a few seconds only with a g-suit and straining technique.
What is a Gal in acceleration?
A Gal is 1 cm/s², or 0.01 m/s². Geophysicists use it, and Earth's gravity is about 980.665 Gal. A milligal is a thousandth of that.