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

Inertia Kg Square Meters (kg·m²)

Required number input.

Angular Speed Radians Per Second (rad/s)

Required number input.

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

Energy Joules (J)

The resulting energy joules 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.

• Flywheel Mass Inertia

  Mass moment of inertia of a uniform solid disk flywheel about its center axis: I=½mr².

• Battery Energy Density

  Gravimetric battery energy density from usable watt-hours divided by battery pack mass in kilograms.

• Critical Shaft Speed

  Undamped first critical rotational speed estimated from a measured static shaft deflection under gravity: n=30√(g/δ)/π.