Enter the mass in kilograms and the acceleration in m/s².
About this calculator
Newton’s second law says force equals mass times acceleration. This calculator gives the force in newtons and in kilogram-force.
Enter the values in the units shown next to each field; the calculator converts what it needs and shows the formula with your numbers.
When to use it
- Engineering estimates.
- Understanding car or lift forces.
- Physics and science homework.
- Checking an exam answer.
How to read the result
F = m × a.
1,200 kg accelerating at 2.5 m/s² needs 3,000 N, about 306 kgf.
Mistakes to avoid
- Confusing mass (kg) with weight (N).
- Mixing units (km/h and m/s, g and kg).
- Rounding intermediate results.
Formula
F = m × a
Worked example
A 1,200 kg car accelerating at 2.5 m/s² needs 3,000 N.
Frequently asked questions
What is a newton?
The force that accelerates 1 kg by 1 m/s².
What is weight?
Mass times gravity: on Earth, 1 kg weighs about 9.81 N.
What is a kilogram-force?
The weight of 1 kg on Earth, 9.80665 N.
What is a newton?
The force that accelerates 1 kg by 1 m/s².
Which units does it use?
SI units unless the field says otherwise.
Are the results exact?
They follow the formula; real situations add friction, losses and other effects.
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Results are estimates for information only. Check important figures with a professional.