# Force Calculator (F = ma)

URL: https://speedycalculator.com/calculators/physics/force/
Last updated: 2026-10-25

> The force calculator applies Newton’s second law, F = ma, to find the net force needed to give a mass a certain acceleration. Type a force to solve for acceleration, in newtons, pounds-force or kilograms-force.

## Inputs

- Mass (kg, lb, g, oz, st)
- Acceleration (m/s², ft/s², g)

## Results

- Net force
- Weight of the mass on Earth

## Formula

```
F = m × a
```

## Explanation

Newton’s second law links force, mass and acceleration: the same push accelerates a light object more than a heavy one.

### How to use the Force Calculator

- **Mass**
- **Acceleration**
- Want to work backwards? Type a value into **Net force** and **Acceleration** is calculated for you.

Results update as you type, and every field accepts the units shown in its menu.

### How it works

Multiply mass in kilograms by acceleration in metres per second squared to get force in newtons.

### Inputs explained

FieldWhat to enterMassUnits: kg, lb, g, oz, stAccelerationUnits: m/s², ft/s², g

### What each result means

- **Net force** = [Mass] × [Acceleration]
- **Weight of the mass on Earth** = [Mass] × g

### Example values

How the main result changes when **Acceleration** changes and everything else stays at the example values above:

Acceleration (m/s²)Net force (N)1.51,8002.252,70033,6003.754,5004.55,40067,200

## Worked example

Inputs — Mass: 1,200 kg; Acceleration: 3 m/s².

Results — **Net force = 3,600 N**; Weight of the mass on Earth = 11,767.98 N.

## Key terms

- **Net force**: The vector sum of all forces on an object.

## FAQ

**What is a newton?**
The force that accelerates 1 kg at 1 m/s².

**Is this the only force acting?**
F is the net force; friction and drag must be added or subtracted.

**What formula does the Force Calculator use?**
F = m × a.

**Can I work backwards from the result?**
Yes. Type the result you want into Net force and the calculator finds the matching acceleration.


## Sources

- [NIST – Fundamental physical constants](https://physics.nist.gov/cuu/Constants/)