Use this engineering calculation for a transparent preliminary estimate or independent arithmetic check when geometry, materials, loads, operating conditions, and units are defined consistently.

Mass Kilograms (kg)

Required number input.

Radius Meters (m)

Required number input.

Mass moment of inertia of a uniform solid disk flywheel about its center axis: I=½mr². The tool evaluates the supplied inputs together and returns the named outputs below; it does not infer omitted operating conditions or change the units shown.^[1]

Inertia Kg Square Meters (kg·m²)

The resulting inertia kg square meters returned as a number.

• Flywheel energy and inertia depend on the actual mass distribution and speed. Material strength, stress concentration, rotor dynamics, containment, bearings, losses, overspeed, balance, and fatigue constrain usable energy.
• Use finite inputs in the displayed units and preserve more precision than the final presentation requires. Independently verify safety-critical, financial, compliance, or production decisions.

Check assumptions against drawings, measurements, current material data, and the applicable design code. Apply required load combinations and safety factors, then obtain qualified review and testing for consequential designs.

• Moment Inertia Rectangle

  Centroidal second moment of area for a solid rectangle about the axis parallel to its width: bh³/12.

• Flywheel Kinetic Energy

  Rotational flywheel kinetic energy ½Iω² from mass moment of inertia and angular speed.

• Moment Inertia Circle

  Centroidal second moment of area of a solid circular section about any in-plane diameter: πd⁴/64.