Moment of inertia of a particle about an axis is equal to the product of the mass of the particle and square of its distance from the axis.
The formula for Moment of Inertia of a particle is given as,
Moment of inertia of the particle about the axis = mass of the particle (m) × distance of particle (r)
from the fixed axis
Formula for Moment of inertia of the particle about the axis = mr2
The S.I. unit for moment of inertia is kg m2