Both the SG90 and the MG996R are hobby servo motors you can control from a single Arduino pin. But one is a tiny 9-gram plastic servo and the other is a beefy metal-gear motor with roughly five times the torque. Using the wrong one either wastes money or leaves your project too weak to move.
Side-by-side comparison
| SG90 | MG996R | |
|---|---|---|
| Weight | ~9 g | ~55 g |
| Torque | ~1.8 kg·cm | ~9–11 kg·cm |
| Gears | Plastic | Metal |
| Rotation | 0–180° | 0–180° |
| Voltage | 4.8–6V | 4.8–7.2V |
| Current draw | Low | High (needs own supply) |
| Best for | Light, precise moves | Heavy, high-force moves |
Torque is the whole story
Torque is the turning force a servo can produce. The SG90’s ~1.8 kg·cm is plenty to swing a small sensor or wave a light arm. The MG996R’s ~9–11 kg·cm can drive a steering linkage, lift a loaded robot arm, or move a door latch. If your servo has ever “buzzed” and failed to move something, you needed more torque — that is the MG996R’s job.
Metal gears vs plastic gears
The SG90 has plastic gears. They are fine for gentle use, but a jam or a sharp knock can strip a tooth and ruin the servo. The MG996R has metal gears that shrug off the same abuse, which is why it is the default choice for robot arms and RC steering where the servo takes real load.
Watch the power supply
An SG90 will usually run happily from the Arduino’s 5V pin. The MG996R draws far more current, especially when it starts moving, and will brown out and reset your Arduino if you power it from the board. Give the MG996R its own 5–6V supply and join the grounds — this is the single most common mistake with big servos.
Choose the SG90 if…
- You’re building a pan-tilt camera or sensor mount.
- You need many servos cheaply — a light robot arm, a walking robot.
- The moving part is light and you value low cost and low current.
Choose the MG996R if…
- Your servo must lift or push real weight.
- You’re building RC steering, a strong robot arm joint, or a latch/gate.
- You’ve already burned out an SG90 on the same job.
What about the MG90S?
There’s a useful middle option: the MG90S. It is the same tiny size as the SG90 but with metal gears, so it survives more abuse while staying light. If you like the SG90’s size but keep stripping gears, the MG90S is the upgrade. There’s also an SG90 360° continuous-rotation version for when you want a small wheel motor rather than a positioning servo.
Frequently asked questions
Can I control both from an Arduino?
Yes — both use the standard 3-wire servo signal and the Arduino Servo library. The difference is power: the SG90 can share the Arduino’s 5V, the MG996R needs its own supply.
Why does my Arduino reset when the MG996R moves?
The servo is drawing too much current from the board. Power it separately from a 5–6V source and connect the grounds together.
Which is better for a robot arm?
MG996R for the heavy base and shoulder joints; SG90 or MG90S for the light wrist and gripper.
Do they rotate a full 360°?
The standard versions rotate 0–180° for positioning. For continuous spin, use a 360° continuous-rotation servo instead.
Related guides
Get your servo
Everything here is in stock at Smart Home | Arduino Corner — Shaheen Market, DAV College Road, Rawalpindi — with same-day delivery in the twin cities and cash on delivery across Pakistan. Compare the SG90 Micro Servo, MG90S Metal-Gear Servo and MG996R High-Torque Servo, or browse all motors & drivers. Tell us what it has to move and we’ll recommend the right torque.