Lever Balance Calculator
Find the effort force needed to balance a load about a fulcrum. Compare perpendicular moment arms, torque and ideal mechanical advantage.
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Result
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Calculation steps
Work through one step at a time or reveal the complete calculation. The steps use your current inputs.
How to calculate
Balance clockwise and counterclockwise moments. Multiply load force by its perpendicular distance from the fulcrum, then divide by the effort’s perpendicular moment arm.
Fload×dload=Feffort×deffort
Worked example
A100N load at20cm from the fulcrum balances with40N effort at50cm. Both moments are20N·m and ideal mechanical advantage is2.5.
Assumptions and input details
Both moment arms must be positive and must be perpendicular distances to the force lines, rather than arbitrary sloping beam lengths. Load and effort moments act in opposite rotational senses. Neglect the lever’s own weight, bearing friction and deformation. Entered base-unit magnitudes are limited to1e12 unless a tighter limit is stated. Results use floating-point arithmetic. These are ideal-model estimates, not equipment load ratings.
References: OpenStax simple machines
Unit definitions
Unit selection is independent of language. Each selector contains only units for its physical quantity. Calculations use defined base units internally.
Choose from 23 length definitions, including explicitly labelled regional measures. Area conversions square the length factor; geometric volumes cube it.
Regional measures are not interchangeable merely because their names look similar. This is a documented selection, not a claim to include every historical unit.
NIST measurement tables · Japanese traditional units · Mainland China and Hong Kong unit distinctions
Using this calculator
Can I enter my own problem?
Yes. Replace the example values with your own inputs. The result, calculation steps, tables and applicable diagrams update from those inputs. Blank or invalid values clear the result; example values are never silently substituted for missing inputs.
Are the results exact?
Results use floating-point arithmetic and displayed rounding. Read the formula, assumptions and any stated data precision before interpreting the result.
Is my input uploaded?
The calculation runs in your browser. No account, file upload or external AI service is required. Inputs are not saved between page reloads.
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