Physics

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Fulcrum Calculator.

Solve an ideal lever torque balance.

On-device calculationNo signup
01

Set your values

Results update as you type.

Load force: 400 N

Load force

0.000000N
Effort torque: 100 N·m

Effort torque

0.000000N·m

Results update automatically as you type.

Use Cases

Physics homework and exam prep

Quickly verify torque balance problems involving levers. Enter effort force, effort arm, and load arm to find the load force, or rearrange to solve for other variables.

Example: A 200 N effort force at 0.5 m from fulcrum balances a load at 2 m. Find the load force.

Simple machine design and analysis

Estimate the required effort force or arm lengths for a lever system to lift a known load, aiding in initial design calculations.

Example: Determine the effort force needed to lift a 500 N load with a 1 m effort arm and 0.2 m load arm.

Frequently Asked Questions

How does the Fulcrum Calculator work?
It applies the principle of moments (torque balance) for an ideal lever: effort force × effort arm = load force × load arm. Enter any three of the four values (effort force, effort arm, load arm, and load force) to calculate the missing one. The calculator uses the given effort force, effort arm, and load arm to compute the load force.
What units are used in the Fulcrum Calculator?
Effort force is entered in newtons (N), and both effort arm and load arm are entered in meters (m). The calculated load force will be in newtons (N). Ensure all inputs are in these units for accurate results.
Can I use this calculator for real-world levers?
Yes, for ideal levers where friction and lever mass are negligible. It's useful for physics problems, simple machine analysis, and educational purposes. For real levers, consider efficiency and other factors, but this provides a good baseline.

Tips & Common Mistakes

Tips

  • Ensure all inputs are in the correct units: newtons for forces and meters for arm lengths.
  • If you know the load force and want to find the effort force, you can rearrange the formula manually or use the calculator by entering the known values.
  • For a balanced lever, the product of effort force and effort arm must equal the product of load force and load arm.
  • Remember that this calculator assumes an ideal lever with no friction and negligible mass.

Common Mistakes to Avoid

  • Using inconsistent units, such as centimeters for arm length instead of meters, which leads to incorrect results.
  • Confusing effort arm and load arm – the effort arm is the distance from the fulcrum to the effort force, and the load arm is the distance to the load.
  • Forgetting that the calculator solves for load force based on the given effort force, effort arm, and load arm; it does not calculate all variables simultaneously.

Last updated: August 13, 2026