A worked example: 1 g to m/s²
1 standard gravity (1 g) converts to exactly 9.80665 m/s² — the internationally agreed reference value for Earth's gravitational acceleration.
The formula: convert through a common base unit
Every acceleration unit is defined by a fixed factor relative to meters per second squared; converting from one unit to another multiplies by the source unit's factor and divides by the target unit's factor. 5 g converts to 49.03325 m/s² — exactly 5 times the 1 g figure, since g-to-m/s² conversion is a straight multiplication.
Converting the other direction: m/s² to ft/s²
100 m/s² converts to 328.08399 ft/s², and 3 g converts to 96.522146 ft/s² — the same underlying 9.80665 m/s²-per-g constant, just carried through an extra unit conversion step to reach feet instead of meters.
Why g-force is a physical constant, not an arbitrary unit
Unlike a purely definitional unit conversion (like feet to meters, which is just a fixed ratio by definition), g-force is anchored to a measured physical quantity — Earth's average surface gravity — that happens to have been standardized to an exact value, 9.80665 m/s², for the purposes of unit conversion, even though actual local gravity varies slightly by location.