SG90 Servo Motor Specs | 9g Micro Servo Spec Overview

The SG90 is a 9 g plastic-gear micro servo that runs on 4.8–6 V and produces about 1.8 kgf·cm of stall torque.

The SG90 is the default micro servo in countless Arduino and Pi projects, but the published specs can disagree by nearly 50% depending on which datasheet you open. You’ll find the SG90 servo motor specs listed with different voltage, torque, and speed figures across sellers, so here’s what the TowerPro product page and common datasheets agree on—and where they diverge.

This guide covers the core numbers you actually need—weight, dimensions, torque, speed, voltage, and the PWM control signal—plus the naming and compatibility caveats that trip up first-time builders. A wrong voltage assumption can burn the servo, and a wrong torque estimate can stall your whole project before it runs.

What Are the Common SG90 Specs?

Most SG90 units share the same core profile: a 9 g plastic-gear micro servo with a roughly 180° rotation range and a standard 3-wire JR/Futaba-compatible plug. The table below compiles the most commonly published values, with the conflicts called out.

Treat these numbers as a baseline rather than gospel. The 9 g weight and 180° range are consistent across nearly every source; torque, speed, and voltage drift between listings. When a spec matters for your build, open the PDF for the exact unit you bought.

Part of the confusion comes from the name itself. TowerPro’s SG90 Digital product page labels the SG90 “Digital,” while most third-party documentation treats it as an analog micro servo. Multiple listings carry different specs, which means the SG90 name covers several non-identical variants rather than one fixed SKU. Some sellers label units “metal gear,” but the widely documented version uses plastic/POM gears. If you’re buying multiples, try to stick to the same seller and batch, because horn shapes and spline sizes can vary slightly.

The output spline is listed as 21T on some datasheets, which matters if you’re buying replacement horns.

How Is the SG90 Controlled and Wired?

The SG90 uses a standard PWM servo signal, normally a 20 ms (50 Hz) pulse train, to set its position. The pulse width maps the angle: many guides use 1 ms to 2 ms for full travel, while TowerPro’s documentation lists 500 µs to 2500 µs. Some clones use a narrower mapping, so if your unit doesn’t center at 1.5 ms, check its datasheet.

Wiring is straightforward—signal, VCC, and ground on the 3-pin JR/Futaba plug—but the servo needs its own 4.8–6 V supply. Don’t power it from a microcontroller’s logic pin; under load it draws far more current than a GPIO can supply. Arduino’s Servo library and Raspberry Pi’s pigpio both handle the 50 Hz signal without extra hardware, making either board an easy control platform. The standard plug order is signal, VCC, ground—usually orange, red, and brown, but confirm the order on your specific unit.

SG90 Limitations and Safe Use

The SG90 is built for light-duty hobby use, not high-torque or continuous industrial work. Its plastic gears are the limiting factor, so never force the horn past the mechanical stop—with about 180° of travel, pushing further can strip teeth. The commonly listed operating range of 0°C to 55°C suits indoor robotics; treat wider ranges on some listings with caution.

Stall current rises sharply under load, and several retailer specs show it exceeding 1 A on some variants, which matters when you design the power rail. Because voltage and torque specs vary across versions, always verify the exact unit’s datasheet before committing to a motor driver or battery budget.

If you’re ready to mount it, our tested roundup of the best arms for the SG90 shows which mounting options hold up under real use.

Keep the supply at 4.8–6 V, respect the 180° stop, and check the exact variant’s datasheet before you build around it.