ONE FORMULA, ONE ANSWER
Point-mass moment of inertia calculator
Sum the moment of inertia of a list of point masses using perpendicular distances to one stated axis. Choose input units and calculate one value within the stated conditions.
Inputs
Calculations run in this browser. Scientific notation such as 1.2e-3 is supported. Do not group thousands.
Result
Moment of inertia about the stated axis I
Enter values and select Calculate.
I = Σ mᵢ rᵢ²
Assumptions
Required: each rᵢ is the shortest perpendicular distance to the same rotation axis. Every entry is a point mass; each component’s intrinsic moment of inertia is excluded. A point on the axis has rᵢ = 0. The list supports 1 to 100 entries.
Displayed values are floating-point approximations. Design safety factors and unprovided error contributions are not calculated.
Formula references and credits
NaNa Lab created the code, descriptions, icons and preview images. Text, figures and code from the linked references have not been reproduced.
Physical constants: NIST / CODATA 2022. The values of μ₀ and ε₀ are measured recommendations, not exact defining constants. Values and precision notes are in the source record.
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