Force Converter
Convert between Newtons, kilonewtons, pound-force and kilogram-force — and discover how much you'd weigh on every planet in the solar system.
FORCE CONVERTER
SI units
Other units
Enter a force to see a real-world comparison
Famous forces — click to load
Step-by-step solution
Type a force to see the conversion working
Weight on other worlds
Enter a mass in kg — see the weight force on each body
⚡ F = ma — Newton's second law
Force = mass × acceleration
A force of 1 Newton accelerates a 1 kg mass at 1 m/s².
Weight = mass × g
Weight is the force of gravity acting on a mass. On Earth, g = 9.81 m/s², so a 1 kg mass has a weight of 9.81 N — but its mass is always 1 kg wherever it is.
Key force facts
Real-world forces
Force Converter Explained
Core concepts, classroom applications, and plain-English explanations for all audiences.
Where you'll actually use this
Every car advert quotes torque in Newton-metres (Nm) — that's a force. Weightlifters talk about lifting 100 kg, but the actual force their muscles generate is 980 N (100 × 9.81). Engineers designing bridges calculate loads in kilonewtons. Unit converters like this one let you move fluently between all of them.
Worked example
"A car engine produces 350 Nm of torque. A weightlifter claims they can match it. Who wins?"
350 Nm = 350 N of force at 1 m radius
Weightlifter lifting 200 kg: 200 × 9.81 = 1,962 N
Result: The weightlifter generates far more force — torque and force aren't the same thing
Tip: force (N) and torque (Nm) are related but different — torque is force × distance.
Common mistake to avoid
- ✗ Confusing mass and weight: 70 kg is a mass. The weight (force of gravity on it) is 70 × 9.81 = 686.7 N. Mass doesn't change; weight does — on the Moon, you'd weigh about 114 N.
The key formula
F = ma — Force equals mass × acceleration. 1 Newton accelerates 1 kg at 1 m/s². Everything else follows from that.
Understanding Force and Its Units
Force is a fundamental concept in physics, representing a push or a pull that can cause an object to accelerate, decelerate, or change direction. It's what makes things move, stop, or deform.
The standard international (SI) unit for force is the Newton (N), named after Sir Isaac Newton. One Newton is defined as the force required to accelerate a mass of one kilogram at a rate of one metre per second squared (1 N = 1 kg·m/s²).
Our Force Converter helps you seamlessly switch between various units of force, including Newtons (N), kilonewtons (kN), meganewtons (MN), pound-force (lbf), kilogram-force (kgf), and dyne. This is particularly useful for GCSE Physics students tackling F=ma and Weight=mg calculations, as well as for engineers working with different measurement systems.
A critical distinction in physics is between mass and weight. Mass is a measure of the amount of matter in an object (measured in kilograms, kg), while weight is the force of gravity acting on that mass (measured in Newtons, N). On Earth, 1 kg of mass weighs approximately 9.81 N. Our calculator includes a 'Planet Weight' feature to demonstrate how your weight changes across different celestial bodies, while your mass remains constant.
Common mistakes to avoid
- My weight is 70 kg:Kilograms (kg) measure mass, which is the amount of matter in an object. Weight is a force, measured in Newtons (N), caused by gravity acting on that mass. My mass is 70 kg, and my weight on Earth is approximately 687 N.
- The force needed to lift this box is 10 kg:Force, including the force needed to lift an object, is measured in Newtons (N), not kilograms (kg). Kilograms measure mass. The force needed to lift this box is approximately 98.1 N (if its mass is 10 kg).
- My weight would be the same if I went to the Moon:Weight depends on the gravitational field strength of the planet or moon you are on. The Moon has a much weaker gravitational field than Earth. My mass would be the same on the Moon, but my weight would be significantly less because the Moon's gravity is weaker.
- I can use F=ma to calculate my weight on Earth by just picking any acceleration 'a':While weight is a force, the 'a' in F=ma refers to acceleration. For weight, the acceleration is specifically the acceleration due to gravity, 'g'. So, the formula for weight is W=mg. To calculate my weight, I use the formula W=mg, where 'm' is my mass and 'g' is the gravitational field strength (approximately 9.81 N/kg on Earth).