Find your weight on other planets and moons.
Mass is a property of your body and does not change anywhere in the universe; weight is the gravitational force acting on that mass and scales directly with the local surface gravity. Mars pulls at 3.72 m/s squared against Earth's 9.81, so a 70 kg person weighs the equivalent of 26.6 kg there. The jump multiplier is the inverse ratio, because the same launch energy converts into height in inverse proportion to gravity.
Weight from surface gravity
gravity ratio = body gravity / 9.80665; weight there = Earth weight x ratio; weight in newtons = mass kg x body gravity; jump multiplier = 9.80665 / body gravity
Because surface gravity depends on mass divided by radius squared, and Jupiter is enormous in both. Its 2.53 times Earth gravity is far less than its 318 times Earth mass would suggest, since the cloud-top radius is eleven times Earth's.
Because Neptune is denser. Uranus has a slightly larger radius but appreciably less mass, so the mass-over-radius-squared ratio lands lower at 8.69 against Neptune's 11.15 m/s squared.
Strictly no — kilograms measure mass and newtons measure weight. But because everyday scales are calibrated for Earth gravity, showing the answer in the same unit you entered is the intuitive comparison, and the newton figure gives the physically correct force.