How to use the rod moment of inertia calculator
Compute the moment of inertia of a thin uniform rod about its centre or about one end. Enter rod mass, rod length in the fields above; the about centre, about one end, radius of gyration about centre are computed instantly and plotted on the chart so you can see how the answer changes.
Common searches this calculator answers include “rod rotation inertia”, “moment of inertia of a stick”, “baton spin”, “calculate rod moment of inertia”, “find about centre”.
Formula
Variables
- m — Rod mass (kg)
- L — Rod length (m)
Worked example
With rod mass = 2 kg, rod length = 1.5 m, the calculator gives about centre ≈ 0.375 kg·m²; about one end ≈ 1.5 kg·m²; radius of gyration about centre ≈ 0.4330127 m.
Frequently asked questions
What is the rod moment of inertia calculator used for?
Compute the moment of inertia of a thin uniform rod about its centre or about one end. It helps with questions such as “rod rotation inertia”, “moment of inertia of a stick”, “baton spin”.
What is the formula for the rod moment of inertia calculation?
About centre (kg·m²) = m × L × L / 12. About one end (kg·m²) = m × L × L / 3. Radius of gyration about centre (m) = √(L × L / 12). Here m is rod mass (kg), L is rod length (m).
What inputs do I need for the rod moment of inertia calculator?
You need rod mass in kg, rod length in m. Each field is pre-filled with a typical example so you can see how the result responds as you edit the numbers.
How do I use the rod moment of inertia calculator?
Type values into the input fields. Results and the chart update instantly. Use Reset to restore the example values, Copy results to paste them elsewhere, or Share to copy a link that preserves your inputs.
Is the rod moment of inertia result exact?
Calculations use standard formulas and double-precision arithmetic, then display about seven significant figures. Real-world measurements carry uncertainty, so treat results as estimates unless your inputs are exact.