# Fulcrum Calculator

URL: https://speedycalculator.com/calculators/physics/fulcrum/
Last updated: 2026-10-30

> The fulcrum calculator finds where to place the fulcrum (or load or effort) on a first-, second- or third-class lever of given length so that an effort balances a load, plus the mechanical advantage.

## Inputs

- Lever class
- Lever length L (m, cm, mm, km, in, ft, yd, mi)
- Load force F_l (N, kN, MN, mN, lbf, kgf, dyn)
- Effort force Fₑ (N, kN, MN, mN, lbf, kgf, dyn)

## Results

- Load arm d_l (fulcrum to load)
- Effort arm dₑ (fulcrum to effort)
- Mechanical advantage
- Possible?

## Formula

```
Fₑ·dₑ = F_l·d_l · Class I: d_l = L·Fₑ/(Fₑ + F_l) · Class II: d_l = L·Fₑ/F_l · Class III: dₑ = L·F_l/Fₑ
```

## Explanation

Archimedes said he could move the Earth with a long enough lever. Seesaws (class I), wheelbarrows (class II) and tweezers (class III) all balance effort and load around a fulcrum by the law of the lever.

### How to use the Fulcrum Calculator

- **Lever class**
- **Lever length L**
- **Load force F_l**
- **Effort force Fₑ**

Results update as you type, every field has its own unit menu, and everything is calculated in your browser.

### How it works

Choose the lever class and enter the lever length, the load and the effort available.

### Inputs explained

FieldWhat to enterLever classChoose one: Class I (fulcrum in the middle), Class II (load in the middle), Class III (effort in the middle)Lever length LUnits: m, cm, mm, km, in, ft …Load force F_lUnits: N, kN, MN, mN, lbf, kgf …Effort force FₑUnits: N, kN, MN, mN, lbf, kgf …

### Example values

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

Lever length L (m)Load arm d_l (fulcrum to load) (m)10.28571.50.428620.57142.50.714330.857141.1429

## Worked example

Inputs — Lever class: Class I (fulcrum in the middle); Lever length L: 2 m; Load force F_l: 500 N; Effort force Fₑ: 200 N.

Results — **Load arm d_l (fulcrum to load) = 0.5714 m**; Effort arm dₑ (fulcrum to effort) = 1.4286 m; Mechanical advantage = 2.5 ×; Possible? = Yes.

## Key terms

- **Fulcrum**: The pivot point of a lever.

## FAQ

**What are the three classes of levers?**
They differ by whether the fulcrum, load or effort is in the middle.

**Can a class III lever give mechanical advantage?**
No – it trades force for speed and range of motion.

**Why is a wheelbarrow class II?**
The load sits between the wheel (fulcrum) and your hands.

**Does the lever's weight matter?**
Yes in practice; this calculator assumes a weightless lever.


## Sources

- [OpenStax – University Physics Volume 1](https://openstax.org/details/books/university-physics-volume-1)
- [The Engineering ToolBox](https://www.engineeringtoolbox.com/)