At its "surface," Neptune has a gravitational acceleration only 14 percent stronger than is felt on Earth. Though Neptune is 17 times more massive than Earth, it has a diameter 3.8 times higher and is therefore considerably less dense than Earth.
Neptune is a gas giant planet, and therefore it doesn't have a solid surface analogous to that of the Earth. Astronomers define the surface of a gas giant as the point in its atmosphere where the pressure is equal to 1 bar, the standard sea-level pressure on Earth. A 100-kilogram person at this point on Neptune would weigh 114 kilograms.