In more detail
Mass, in kilograms, is the same everywhere; weight is a force, in newtons, and depends on local gravity: W = m × g, with standard gravity 9.80665 m/s². On Earth, g ranges from about 9.78 m/s² at the equator to 9.83 at the poles, and on the Moon it is 1.62, about one sixth. Bathroom and kitchen scales measure force and divide by an assumed g to show kilograms, while a balance compares two masses and reads the same anywhere. Imperial units have the same split between the pound-mass and the pound-force.
Why it matters
Physics and engineering calculations need weight in newtons, not kilograms, or every force comes out wrong by a factor of about 9.8. A spring scale calibrated in one place reads slightly differently in another, which is why trade scales are calibrated where they are used. Astronauts in orbit are weightless but keep all their mass, so moving heavy objects still takes effort.
Example
70 kg on Earth: 70 × 9.80665 = 686.5 N
70 kg on the Moon: 70 × 1.62 = 113.4 N (0.165 of the Earth value)
Spring scale calibrated at the equator (9.780) used at a pole (9.832): 70 kg reads 70.37 kg