Servo Motor vs Stepper Motor: What Is the Difference and Which to Choose?
Learn how servo and stepper motors differ in operating principle, feedback, speed-torque behaviour, accuracy and cost, and choose the right one for your application.
What is the difference between a servo motor and a stepper motor? A stepper motor turns its shaft by a fixed angle (usually 1.8°) for each pulse from the drive and usually runs open loop without feedback. A servo motor runs closed loop: its drive continuously corrects it using position and speed information from the encoder on the shaft. A stepper motor delivers high torque at low speeds and costs less; a servo motor maintains its torque at high speed, does not lose position when the load changes and is preferred for dynamic applications.
Comparison table
| Property | Stepper motor | Servo motor |
|---|---|---|
| Control | Open loop; position is known from the number of pulses sent | Closed loop; continuously corrected with encoder feedback |
| Speed-torque behaviour | High torque at low speed, dropping markedly as speed rises | Torque largely maintained up to rated speed |
| Overload | Misses steps if the load exceeds motor torque, and the drive does not know | Can deliver short-term overload torque; position error is detected by the drive |
| At standstill | Provides holding torque while energised and may heat up | Draws only as much current as the load requires to hold position |
| Setup | Simple; current and microstepping are selected | Gain and parameter tuning required |
| Cost | Lower | Higher |
| Catalog | Stepper Motor Systems | Servo Systems |
Which one should I choose?
- A stepper motor is sufficient for low to medium speed positioning where the load is constant and predictable: small CNC and laser cutters, 3D printers, dosing and labelling machines, adjustment spindles.
- A servo motor is chosen where high speed, fast acceleration, variable loads and position security are required: CNC machine axes, packaging and filling machines, robots, flying-cut and synchronised axes.
- Closed-loop stepper systems with an encoder are an intermediate solution for applications that want to reduce the risk of missed steps without the cost of a servo.
Drive and power supply
Both motors run with a drive suited to their type; motor and drive are selected together in terms of current, voltage and encoder type. Stepper motors use stepper drives, servo motors use the servo drives matched by the manufacturer.
Related guides
- What Is a Servo Motor? How It Works, Types and Selection
- Stepper motors selection guide
- Stepper drives selection guide
- Servo drives selection guide
Frequently asked questions
Why does a stepper motor miss steps?
When the torque required by the load or the acceleration exceeds the motor's torque at that speed, the rotor cannot follow the steps sent by the drive and misses steps. In an open-loop system the drive does not detect this, so the position error accumulates. A gentler acceleration ramp, a correctly set drive current, a higher-torque motor or a closed-loop system reduce the problem.
When is a servo motor needed instead of a stepper?
A servo motor is preferred when torque is needed at high speed, when the load varies, when fast starts and stops are required, or when losing position could damage the product or the machine.
What is a closed-loop stepper motor?
It is a stepper motor with an encoder on its shaft whose drive uses this feedback to detect and correct missed steps. It keeps the simplicity and cost advantage of a stepper while improving position security, but the torque drop at high speeds remains typical of a stepper motor.
Can a servo motor be run with a stepper drive?
No. A servo motor runs with its own servo drive, which reads the encoder feedback and is parameterised for the motor type. A stepper drive cannot drive a servo motor; motor and drive are selected together according to the manufacturer's compatibility list.