Motors & Motion Calculator

Servo Motor Torque Calculator

Estimate running torque, acceleration torque, recommended motor torque, reflected inertia, and motor power for linear or rotary motion systems.

Use this for early servo sizing, concept design, pulley-driven axes, conveyor-style drives, rotary indexers, and rough motor selection in industrial automation equipment.

Good starting use case: use this for early servo sizing before digging into full reflected inertia models, detailed move profiles, gearbox backlash, gravity loading, regeneration, and vendor torque-speed curves.

What this calculator gives you

  • Motor running torque
  • Motor acceleration torque
  • Total estimated motor torque
  • Recommended torque with safety factor
  • Reflected inertia and estimated motor power

Recommended Servo Sizing Workflow

Servo sizing is more than torque. Use this first-pass estimate, then check gear ratio, reflected inertia, speed limits, duty cycle, and vendor torque-speed curves.

Typical motion design path

Start with motion torque, then verify gearing, output torque, speed, and related mechanical assumptions.

Estimate Servo Motor Torque

Estimate running torque, acceleration torque, total motor torque, recommended motor torque, reflected load inertia, and estimated motor power.

For this simplified model, the main load input is treated as a force-equivalent load in pounds. Use it for early estimating, not as a final motor sizing calculation.

Total Motor Torque = Running Torque + Acceleration Torque

Recommended Torque = Total Motor Torque × Safety Factor

Quick examples

Linear Geared Axis

Useful for belt, pulley, wheel, and conveyor-style motion with reduction.

Rotary Indexer

Useful for indexing tables or rotating loads with external inertia.

Direct Drive

Useful for a simple first-pass direct-drive axis estimate.

Enter values and press Calculate Servo Torque.

My Saved Servo Torque Calculations

Save servo torque setups, reload previous inputs, and reuse common motion sizing checks.

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This is a practical first-pass sizing calculator. Final servo selection should still consider true reflected inertia from all rotating components, move profile shape, gravity loads, gearbox backlash, duty cycle, shock loading, regenerative effects, and vendor torque-speed curves.

Where this helps

  • Early servo sizing
  • Rotary indexer concepts
  • Belt or pulley-driven axes
  • Conveyors and direct-drive review
  • Motion concept screening

Common next checks

  • Full reflected inertia model
  • Move profile shape and duty cycle
  • Gravity load and holding torque needs
  • Gearbox backlash and stiffness
  • Vendor torque-speed curve limits

Important reminder

A servo may pass the estimated torque calculation but still fail the application if the motor cannot provide the torque at the required RPM, if the reflected inertia ratio is poor, or if the duty cycle creates too much heat.

Continue the Motion Design

This tool gives a strong first-pass servo estimate, but real motor selection changes quickly once you include full inertia modeling, move profile shape, gravity effects, transmission stiffness, backlash, dwell pattern, and actual duty cycle at speed.

Need Help Applying This on a Real Machine?

If you need help with servo sizing, motion system review, gear ratio decisions, or full machine concept development, use the support path below.

Related Motion Pages

These pages work together when validating gear ratio, servo torque, conveyor speed, and motion-system assumptions.

Need Help With a Servo Application?

Submit your application details for motion sizing, torque review, gear ratio questions, or general servo application help.

Submit Your Application Details

This form is for application questions and general help requests. Final motor selection should still be confirmed with manufacturer tools and application-specific review.