Lever Calculator
Free calculate mechanical advantage, effort force, or load force from lever arm lengths. Get instant, accurate results with our easy-to-use calculator.
Input Parameters
Distance from fulcrum to effort point
Distance from fulcrum to load point
Results
Enter parameters to calculate
What is a Lever?
A lever is a simple machine consisting of a rigid bar that pivots around a fixed point called the fulcrum. Levers amplify force by trading force for distance, allowing you to lift heavy loads with less effort.
The mechanical advantage (MA) of a lever is the ratio of the effort arm length to the load arm length. MA = effort arm / load arm. A higher MA means you need less force to lift a given load, but you must move the effort point a greater distance.
Levers are classified into three types based on the relative positions of the fulcrum, effort, and load. Examples include seesaws (first class), wheelbarrows (second class), and tweezers (third class).
Lever Formulas
Mechanical Advantage
Effort Force
Load Force
Where: d_e = effort arm, d_l = load arm, F_e = effort force, F_l = load force
How to Calculate
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1
Measure arm lengths
Measure distance from fulcrum to effort point (effort arm) and from fulcrum to load point (load arm).
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2
Calculate mechanical advantage
MA = effort arm / load arm. This tells you how much the lever amplifies force.
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3
Apply force balance
For equilibrium: F_e × d_e = F_l × d_l. Use this to solve for unknown force.
Practical Examples
Example 1: Crowbar
Effort arm: 2 m, Load arm: 0.5 m. Calculate mechanical advantage.
Solution:
MA = 2 m / 0.5 m = 4
You can lift 4× the weight with 1/4 the force!
Example 2: Lifting a Load
Load: 100 N, Effort arm: 2 m, Load arm: 0.5 m. What effort is needed?
Solution:
F_e = 100 N × 0.5 m / 2 m = 25 N
Only 25 N needed to lift 100 N load!
Applications
Tools
Crowbars, pliers, wrenches, and other hand tools use levers to amplify force for easier work.
Exercise Equipment
Weight machines, resistance equipment, and gym apparatus use lever principles for force multiplication.
Machinery
Construction equipment, cranes, and mechanical systems incorporate levers for lifting and moving heavy objects.
Education
Teaching simple machines, mechanical advantage, and basic physics principles in science education.
Frequently Asked Questions
What are the three classes of levers?
First class: fulcrum between effort and load (seesaw). Second class: load between fulcrum and effort (wheelbarrow). Third class: effort between fulcrum and load (tweezers).
Does a lever create energy?
No! Levers don't create energy - they trade force for distance. Work input = work output (F_e × d_e = F_l × d_l). Less force means more distance moved.
What is the ideal mechanical advantage?
Ideal MA = effort arm / load arm (assuming no friction). Real MA is lower due to friction and other losses. Efficiency = real MA / ideal MA.
Can MA be less than 1?
Yes! When load arm > effort arm, MA < 1. This means you need more force than the load, but you move the load a greater distance (speed advantage).
How does friction affect levers?
Friction at the fulcrum and contact points reduces efficiency. Real mechanical advantage is lower than ideal. Well-lubricated pivots minimize losses.