Fulcrum Calculator

Find the balance point between two opposing loads on an ideal lever.

Fulcrum position
Enter two forces and their separation to locate the torque-balanced pivot.

About fulcrum position and lever balance

A fulcrum is the pivot around which a lever rotates. When downward forces act on opposite sides, the lever balances only when their moments, or torques, about the fulcrum are equal. This calculator locates that balance point between two forces separated by a known distance. It assumes a rigid, weightless lever, perpendicular forces, and a frictionless pivot. If the left force is F1, the right force is F2, and their total separation is L, equilibrium requires F1d1 = F2d2 and d1 + d2 = L. Solving these equations gives d1 = F2L/(F1 + F2) and d2 = F1L/(F1 + F2). The larger force must be closer to the fulcrum, while the smaller force acts through a longer arm. Equal forces place the fulcrum exactly halfway between them. Force may be entered in newtons and separation in meters as labeled, although the geometric ratio is unchanged if both forces share another unit and all lengths share another unit. The displayed distances follow the entered length unit conceptually, but the interface identifies meters to avoid accidental mixing. If values originate as masses, multiply each mass by the same gravitational acceleration. Since that common factor cancels, masses measured in the same unit can also be compared as proportional loads when local gravity is identical. Real levers add complications. The beam has weight acting at its center of gravity, applied forces may be angled, bearings create friction, and supports have finite width. Each additional load contributes its own signed moment and cannot be represented by this two-load equation without first combining forces and moments correctly. Use this calculator for seesaws, simple balance beams, conceptual statics problems, and preliminary layouts. For structural lifting devices, include self-weight, dynamic loading, material strength, support reactions, and an appropriate safety factor before selecting hardware or approving safe operation.

Fulcrum position examples

InputsDistances from left and rightObservation
100 N left; 50 N right; 3 m apart1 m; 2 mThe pivot is closer to the larger left force.
80 N left; 120 N right; 5 m apart3 m; 2 mThe larger right force receives the shorter arm.
200 N left; 200 N right; 4 m apart2 m; 2 mEqual loads balance at the midpoint.

How to find the fulcrum

  1. Measure the two opposing forces using the same force unit.
  2. Measure the straight-line distance between their application points.
  3. Enter all three positive values and select Find fulcrum position.
  4. Measure the reported distance from either load to place the pivot.

Frequently asked questions

Why is the fulcrum closer to the heavier load?

Torque equals force multiplied by perpendicular distance. A larger force needs a shorter arm to equal the torque produced by a smaller force on a longer arm.

Can I enter mass instead of force?

Proportional masses can be used when both experience the same gravity because the conversion factor cancels. For strict SI calculations, convert mass to force in newtons first.

Does the lever's own weight matter?

Yes, a real lever's weight produces an additional moment at its center of gravity. This two-force calculator assumes that weight is negligible or supported independently.

What if a force acts at an angle?

Only the component perpendicular to the lever creates torque. Resolve each angled force before using this simplified calculation.

What happens when the forces are equal?

Equal opposing forces require equal arm lengths for rotational equilibrium. The fulcrum therefore lies at the midpoint between their application points.