Advanced Shaft Torque Calculator

Analyze shafts with flexible inputs and practical conversions. Estimate torque using four reliable calculation methods. Plot trends, compare outputs, and export neat reports easily.

Calculator Inputs

Primary Calculation Fields

Optional Secondary Analysis

Reset

Example Data Table

Case Method Input Set Torque Result
Drive Motor Power and speed 45 kW, 1450 rpm 296.38 N·m
Pulley Load Force and radius 3200 N, 0.18 m 576.00 N·m
Solid Steel Shaft Solid shaft capacity 65 MPa, 55 mm diameter 1,070.23 N·m

Formula Used

Power and speed
T = 9550 × P(kW) ÷ n(rpm)
Force and radius
T = F × r
Solid round shaft capacity
T = τ × π × d³ ÷ 16
Hollow round shaft capacity
T = τ × π × (Do⁴ - Di⁴) ÷ (16 × Do)
Angle of twist
θ = T × L ÷ (J × G)

Use SI units whenever possible for clean engineering interpretation. The calculator converts entered values first, computes torque in N·m, then reports equivalent units.

How to Use This Calculator

  1. Select the method that matches your known inputs.
  2. Enter values and choose units for every active field.
  3. Add optional geometry if you want stress or twist checks.
  4. Include operating speed to estimate transmitted power.
  5. Press the calculate button to show the result above.
  6. Review the result table, graph, and design notes.
  7. Download CSV or PDF if you need a saved copy.

FAQs

1) What is shaft torque?

Shaft torque is the twisting moment carried by a rotating member. It represents how strongly the shaft turns a load around its axis.

2) Which method should I choose?

Use power and speed for motors, force and radius for pulleys or levers, and shaft capacity methods when sizing solid or hollow shafts from allowable stress.

3) Why does torque decrease when speed rises?

For constant power, torque and speed move inversely. Higher shaft speed means the same power is delivered with less torque.

4) Can I use imperial units?

Yes. Force, diameter, radius, stress, and torque equivalents support common imperial choices, including lbf, inches, feet, psi, lbf·ft, and lbf·in.

5) What is allowable shear stress?

Allowable shear stress is the design limit used to keep torsional stress within safe working conditions. It is usually lower than material yield strength.

6) Why include angle of twist?

Strength alone may be acceptable while stiffness is not. Angle of twist helps check whether the shaft rotates too much under the applied torque.

7) Is hollow shaft analysis useful?

Yes. Hollow shafts often reduce weight while preserving good torsional performance. They are common in drivetrains, machinery, and rotating structural systems.

8) Does this replace full mechanical design?

No. It supports preliminary engineering decisions. Final design should also consider fatigue, stress concentration, shock loading, keyways, misalignment, and safety factors.

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Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.