BYTETOOLS

Force Calculator

Solve Newton's second law F = ma for force, mass or acceleration, plus weight W = mg on Earth, Moon and Mars, with newtons and pounds-force output.

20 N
Force
4.4962 lbf
Pounds-force
10 kg
Mass
2 m/s²
Acceleration

Working

F = m × a = 10 kg × 2 m/s² = 20 N. Conversion: 1 lbf = 4.44822 N. That acceleration is 0.204 g.

What is the Force Calculator?

The ByteTools Force Calculator solves Newton's second law, F = m × a, for whichever variable you leave unknown — force, mass or acceleration.

  • Solves F = ma for force, mass or acceleration
  • Weight mode with gravity presets for 8 solar-system bodies
  • Newtons ↔ pounds-force conversion built in (1 lbf = 4.44822 N)
  • Mass in kg, g or lb; acceleration in m/s² or g-units
  • Formula and substitution printed with each answer
  • 100% private — runs entirely in your browser

How to use the Force Calculator

  1. 1

    Pick the mode: F = ma solver or weight (W = mg).

  2. 2

    Choose which variable to solve for and enter the other two.

  3. 3

    In weight mode, pick a gravity preset (Earth, Moon, Mars…) or enter your own g.

  4. 4

    Read the result in newtons and pounds-force, with the working shown.

  5. 5

    Copy the result with one click.

About the Force Calculator

The ByteTools Force Calculator solves Newton's second law, F = m × a, for whichever variable you leave unknown — force, mass or acceleration. Results are shown in newtons and pounds-force (1 lbf = 4.44822 N), with mass accepted in kilograms, grams or pounds.

A separate weight mode computes W = m × g using standard gravity g = 9.80665 m/s² for Earth, or preset values for the Moon (1.625 m/s²), Mars (3.721 m/s²) and other bodies — a favourite physics-homework comparison. The formula and substituted numbers are printed with every answer.

It is aimed at physics students, teachers and engineers who want a quick, transparent calculation. Everything runs 100% locally in your browser: nothing is uploaded, and the tool works offline.

Frequently asked questions

What is Newton's second law?

It states that the net force on an object equals its mass times its acceleration: F = m × a. A 10 kg mass accelerating at 2 m/s² experiences a net force of 20 newtons. Rearranged, m = F ÷ a and a = F ÷ m, which is exactly what this calculator solves.

What is the difference between mass and weight?

Mass is the amount of matter, measured in kilograms, and is the same everywhere. Weight is the gravitational force on that mass, W = m × g, measured in newtons. A 70 kg astronaut weighs about 686 N on Earth but only about 114 N on the Moon, while their mass never changes.

How many newtons is one pound-force?

One pound-force is exactly 4.4482216152605 newtons — the weight of one pound of mass under standard gravity. To convert, multiply lbf by 4.44822 to get newtons, or divide newtons by 4.44822 to get lbf. The calculator shows both units automatically.

What value of g does the calculator use?

Earth's preset is standard gravity, g = 9.80665 m/s², the internationally agreed reference value. Actual local gravity varies from about 9.78 at the equator to 9.83 m/s² at the poles, so you can type a custom g if you need site-specific precision.

Is F = ma valid at any speed?

It is Newtonian mechanics, accurate for everyday speeds and engineering. At speeds approaching light, relativistic mechanics takes over and F = ma no longer holds in its simple form — but for cars, rockets at launch and projectiles it is an excellent model.

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