How do you convert kg to Newtons?

Multiply the mass in kg by 9.81 (or precise 9.80665). For example, 10 kg × 9.81 = 98.1 N.

Is mass the same as weight?

No. Mass is the quantity of matter (constant). Weight is the force of gravity on that matter (varies by location).

Convert Mass (Kilograms) to Force (Kilonewtons) using standard Earth gravity.

Mass (Kilograms - kg)

⇅

Force (Kilonewtons - kN)

Assumes g = 9.80665 m/s²

In everyday language, we use "weight" to mean mass, but in physics, they are different.

Mass (kg) is the amount of matter in an object. It stays the same wherever you are.
Weight/Force (N) is the force of gravity acting on that mass. It changes depending on gravity (e.g., you weigh less on the Moon).

F = m × a (Newton's Second Law)
On Earth, acceleration (a) is gravity (g) ≈ 9.80665 m/s².

So, Force (Newtons) = Mass (kg) × 9.80665