kg to Newtons Calculator — Mass to Weight Force
Convert a mass in kilograms to a gravitational force (weight) in Newtons using Newton's second law F = m × g. Compare the weight on Earth, the Moon, Mars and other bodies, and see the result in kN, kgf, lbf and dynes.
Conversion direction
kg
Gravitational acceleration
F = m × g (Newton's second law)
- 1
Gravitational acceleration
9.80665 m/s² - 2
Weight F = m × g
10 × 9.80665 = 98.0665Newton's second law: force equals mass times acceleration.
How does this calculator work?
Weight (N) = mass (kg) × g (m/s²). At Earth standard gravity (g = 9.80665 m/s²): 1 kg = 9.807 N, 10 kg = 98.07 N, 100 kg = 980.7 N. On the Moon (g = 1.62 m/s²): 1 kg = 1.62 N. On Mars (g = 3.72 m/s²): 1 kg = 3.72 N.
Formula
How this is calculated
Newton's second law states that force equals mass times acceleration: F = m × a. Gravitational weight is a special case where the acceleration is g, the local gravitational acceleration. At sea level on Earth the internationally agreed standard value is g = 9.80665 m/s² (this exact value is used in the definition of kilogram-force and in many engineering standards). Multiplying a mass of m kilograms by g gives the weight in Newtons.
The local value of g varies slightly: it is higher at the poles (9.8322 m/s²) because the Earth is slightly flattened, and lower at the equator (9.7803 m/s²) because of centrifugal effect and the greater distance from Earth's centre. For most engineering and everyday purposes the standard value 9.80665 m/s² is used.
On the Moon, g ≈ 1.62 m/s² — about 1/6 of Earth's. On Mars, g ≈ 3.721 m/s² — about 38% of Earth's. An astronaut with a mass of 70 kg weighs 686.5 N on Earth, only 113.4 N on the Moon, and 260.5 N on Mars — but their mass stays at 70 kg regardless of location. Note: a kilogram-force (kgf) is defined as the force exerted by 1 kg at standard g, so 1 kgf = 9.80665 N exactly.
Frequently asked questions
1 kg of mass has a weight (gravitational force) of 9.80665 N at Earth's standard gravity. On the Moon (g = 1.62 m/s²) the same mass weighs 1.62 N. On Mars (g = 3.721 m/s²) it weighs 3.721 N.
Kilograms measure mass — the amount of matter in an object, which does not change with location. Newtons measure force — specifically the gravitational pull (weight) exerted on that mass, which varies with g. Your 70 kg body mass is always 70 kg, but your weight changes from 686.5 N on Earth to 113.4 N on the Moon.
A kilogram-force (kgf) is the force exerted by a 1 kg mass at standard gravity (g = 9.80665 m/s²), so 1 kgf = 9.80665 N exactly. It is commonly used in engineering and hydraulics. Note: 1 kgf ≠ 1 kg — kgf is a force unit, kg is a mass unit.
TG we-Calculate Editorial Team. (2026). kg to Newtons Calculator — Mass to Weight Force [Online calculator]. TG we-Calculate. https://we-calculate.com/calculator/kg-to-newtons-calculator
TG we-Calculate Editorial Team. "kg to Newtons Calculator — Mass to Weight Force." TG we-Calculate. 2026. https://we-calculate.com/calculator/kg-to-newtons-calculator.
TG we-Calculate Editorial Team, "kg to Newtons Calculator — Mass to Weight Force," TG we-Calculate, 2026. [Online]. Available: https://we-calculate.com/calculator/kg-to-newtons-calculator
@misc{wecalculate_kg_to_newtons_calculator, title = {kg to Newtons Calculator — Mass to Weight Force}, author = {{TG we-Calculate Editorial Team}}, howpublished = {\url{https://we-calculate.com/calculator/kg-to-newtons-calculator}}, year = {2026}, note = {TG we-Calculate} }
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