Fulcrum Calculator
Balance a lever to find the unknown force.
A lever balances when the torques about the fulcrum are equal on both sides.
How the Math Works
The Fulcrum Calculator uses the fundamental principle of torque equilibrium in levers. When a lever is balanced, the clockwise torque equals the counter-clockwise torque. The formula load = effort × effort arm × load arm expresses this relationship: the force applied to the load side (load) is determined by multiplying the effort force by its distance from the fulcrum (effort arm), then dividing by the distance of the load from the fulcrum (load arm). This inverse relationship means that a larger effort arm allows you to lift heavier loads with less effort force.
Practical Applications
To use this calculator practically, first identify your lever's fulcrum point and measure the distances from this point to where you'll apply the effort force (effort arm) and where the load will be placed (load arm). Input these measurements along with your available effort force, and the calculator will determine the maximum load you can lift. This is essential for designing seesaws, wheelbarrows, crowbars, and other simple machines, or for determining the required effort to move heavy objects using existing tools.
Day-to-Day Use
Understanding lever mechanics helps you work smarter, not harder. When moving furniture, loading a truck, or using tools like pry bars, you can estimate how much force you'll need by adjusting your approach - placing the fulcrum closer to the load to reduce required effort. This knowledge prevents injury, helps you choose the right tool for the job, and allows you to solve everyday problems efficiently, whether you're opening paint cans, lifting heavy boxes, or simply understanding why children and adults can use the same playground equipment safely.
Worked example
50 N on a 2 m arm lifts 200 N on a 0.5 m arm (advantage 4).
FAQ
Where should the fulcrum go for more lift?
Closer to the load, lengthening the effort arm.