Moment of Inertia Converter
Convert moment of inertia (mass × distance squared) between metric and imperial units.
Written by Rahman · Last reviewed
Quick answer
Moment of inertia measures resistance to angular acceleration, depending on both mass and how far that mass sits from the axis. The SI unit is the kilogram square metre; one pound square foot is 0.04214 kg·m². Because distance enters as a square, moving mass outward raises it sharply, which is why a skater spins faster with arms pulled in.
| Kilogram metre² (kg·m²) | 1 |
| Kilogram centimetre² (kg·cm²) | 10000 |
| Gram centimetre² (g·cm²) | 10000000 |
| Pound foot² (lb·ft²) | 23.7303604 |
| Pound inch² (lb·in²) | 3417.171938 |
| Ounce inch² (oz·in²) | 54674.68562 |
About the Moment of Inertia Converter
Moment of inertia describes how mass is distributed around an axis of rotation and how strongly an object resists changes to its spin. The SI unit is the kilogram metre squared.
This converter handles metric and imperial units used in mechanical and structural engineering.
Frequently Asked Questions
What is moment of inertia?
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It is the rotational equivalent of mass: a measure of how hard it is to change an object’s rotation about an axis.
What is the SI unit of moment of inertia?
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The SI unit is the kilogram metre squared (kg·m²).
Why does mass distribution matter?
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Mass farther from the axis contributes far more to the moment of inertia, which is why it depends on shape, not just total mass.