Fulcrum Calculator
Calculate fulcrum position and mechanical advantage for levers
Calculation Mode
Fulcrum Calculator
Fulcrum between effort and load (seesaw, crowbar)
Force or weight to be lifted
Force applied to move the lever
Total length of the lever
Example Calculation
Class I Lever (Crowbar) Example
Load (rock): 500 N
Effort (your force): 100 N
Lever length: 1.5 m
Mechanical advantage: 500/100 = 5x
Fulcrum Position Calculation
For Class I: dr = L / (MA + 1)
dr = 1.5 / (5 + 1) = 1.5 / 6 = 0.25 m
de = L - dr = 1.5 - 0.25 = 1.25 m
Place fulcrum 0.25 m from the load
Lever Classes
Class I Lever
Fulcrum between effort and load
Examples: Seesaw, crowbar, pliers
Class II Lever
Load between fulcrum and effort
Examples: Wheelbarrow, nutcracker
Class III Lever
Effort between fulcrum and load
Examples: Tweezers, human arm
Lever Physics
Law of the lever: Fr × dr = Fe × de
Mechanical advantage = Fr/Fe = de/dr
Longer effort arm = greater mechanical advantage
Fulcrum position determines force multiplication
Trade distance for force or vice versa
Understanding Levers and Fulcrums
What is a Fulcrum?
A fulcrum is the pivot point around which a lever rotates. It's the critical component that enables a lever to multiply force, allowing you to lift heavy loads with less effort by applying the principles of torque and mechanical advantage.
Law of the Lever
- •Forces farther from fulcrum require less magnitude
- •Balance of moments: Fr × dr = Fe × de
- •Mechanical advantage = Load Force / Effort Force
- •You trade distance for force multiplication
Fulcrum Equations by Class
Class I Lever
dr = L / (MA + 1)
Fulcrum between effort and load
Class II Lever
dr = L / MA
Load between fulcrum and effort
Class III Lever
dr = L, de = MA × L
Effort between fulcrum and load
Where: dr = load arm, de = effort arm, L = lever length, MA = mechanical advantage
Practical Applications
Class I Applications
- • Crowbars and pry bars
- • Seesaws and balance scales
- • Pliers and scissors
- • Boat oars
Class II Applications
- • Wheelbarrows
- • Nutcrackers
- • Bottle openers
- • Nail clippers
Class III Applications
- • Human arms and limbs
- • Tweezers and tongs
- • Fishing rods
- • Brooms and mops