Rex says
The fast lane for the math you almost remember from school. Type the numbers, get the answer, move on with your day.
Try a scenario
Click to load — tweak from there.Inputs
Result
Force (N)
50.00
Force (lbf)
11.24
Weight on Earth (N)
98.10
Force (kgf)
5.10
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One click, a permanent link with your numbers baked in.
How to use this
- 1Enter mass (kg).
- 2Enter acceleration (m/s²).
- 3Read your force (n) on the right — it updates as you type.
- 4Hit Share to keep the scenario or send it to someone.
About this calculator
Newton's second law: force equals mass times acceleration. Also converts to pounds-force and shows weight under Earth gravity.
Worked example
Using the values the calculator loads with:
Inputs
- Mass: 10 kg
- Acceleration: 5 m/s²
Results
- Force (N): 50
- Force (lbf): 11.24
- Weight on Earth (N): 98.1
- Force (kgf): 5.1
What each field means
Inputs
- Mass (kg)
- The mass used in the calculation, measured in kg. Starts at 10 kg so you have a working example on load.
- Acceleration (m/s²)
- The acceleration used in the calculation, measured in m/s². Starts at 5 m/s² so you have a working example on load.
Results
- Force (N)
- Returned as a decimal number and shown as the headline result. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Force (lbf)
- Returned as a decimal number. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Weight on Earth (N)
- Returned as a decimal number. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Force (kgf)
- Returned as a decimal number. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
FAQ
How does the force calculator work?
Newton's second law: force equals mass times acceleration. Also converts to pounds-force and shows weight under Earth gravity. The underlying maths is: F = m × a
What do I need to enter?
2 values: mass, and acceleration. Each field starts with a sensible default, so you can change one number at a time and watch the result move.
What does the force (n) result mean?
It is returned as a decimal number and updates live as you edit the inputs, so you can compare two or three versions of a scenario in a few seconds.
Is this calculator free, and do I need an account?
Yes, it's free, and no account is required. Nothing you type is stored on our servers — the maths runs entirely in your browser.
How accurate is the result?
It applies the standard formula exactly, so the arithmetic is precise. Results are rounded for display; the underlying calculation keeps full precision.
Who is this tool for?
It's built for students, developers, and anyone who needs the answer right now without setting up a spreadsheet.
Accuracy and limitations
- Results are rounded for display; the underlying calculation keeps full precision.
- Very large or very small inputs may hit floating-point limits in the browser.
- Inputs outside the accepted range are clamped rather than rejected.
Cite this calculator
Writing about this topic? Grab a citation — every link helps keep these tools free.
RevenueLab. (2026). Force Calculator (F = ma). Retrieved from https://www.revenuelab.fyi/toolbox/force-calculator
<p>Source: <a href="https://www.revenuelab.fyi/toolbox/force-calculator" target="_blank" rel="noopener">Force Calculator (F = ma) — RevenueLab</a> (2026).</p>
Source: [Force Calculator (F = ma) — RevenueLab](https://www.revenuelab.fyi/toolbox/force-calculator) (2026).