A smart plug is a small adapter that sits between a wall outlet and whatever you plug into it. It lets you switch that device on and off from a phone app, a voice assistant or a schedule, so an ordinary lamp, fan or coffee maker becomes controllable without replacing the appliance.
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How a smart plug works
The plug contains a switch and a radio. Most models connect to your home Wi-Fi and are set up in the maker’s app. Others use Zigbee or Thread and need a compatible hub. When you tap the app, ask a voice assistant, or a schedule comes due, the plug opens or closes the switch.
It only controls power to the outlet, so the appliance has to turn on by itself when power arrives. A lamp whose own switch is left on works. A device that waits for a button press after the power comes back does not.
What you can do with one
- Remote on and off from the app.
- Schedules and timers. TP-Link describes the schedule feature on its Kasa KP125M plug as presetting a schedule to manage devices automatically.
- Voice control. The same Kasa plug lists Amazon Alexa, Apple Siri and Google Assistant.
- Away mode on some models, which turns devices on and off at different times so the house looks occupied.
- Energy monitoring on some models, which reports real-time and historical power use for whatever is plugged in. Basic plugs do not measure it. See our guide to home energy monitoring.
What to check before you buy
- Which system it works with. Look for your platform by name on the box, or for the Matter logo. The Connectivity Standards Alliance describes Matter as one protocol to connect compatible devices and systems with one another, and names Amazon Alexa, Apple Siri, google home and Samsung SmartThings among the ecosystems it covers.
- Whether it needs a hub. Wi-Fi plugs usually do not. Zigbee and Thread plugs do.
- Your Wi-Fi band. Many Wi-Fi smart devices join 2.4 GHz networks only. Check the box if your router is set to 5 GHz only.
- The maximum load. Every plug has a rated maximum, printed on the plug or in its manual. Check it before connecting anything with a heating element or a large motor, such as a space heater or an air conditioner.
- Size. A bulky plug can block the second socket. Compact models are sold for that reason.
- Indoor or outdoor. Outside, use a plug that is rated for outdoor use.
What a smart plug cannot do
A standard smart plug switches power and nothing more. It cannot dim a lamp or change a setting on the appliance. For dimming and color, use smart bulbs. Our guide to smart lighting systems covers those.
Related questions
Is a smart plug the same as a smart outlet?
No. A smart plug pushes into an existing outlet and moves with you. A smart outlet replaces the outlet in the wall and has to be wired in.
Does a smart plug use electricity when the device is off?
Yes, a small amount. The plug’s radio stays on so it can receive the next command.
Do smart plugs work without Wi-Fi?
A Wi-Fi plug cannot be reached from the app or a voice assistant while your Wi-Fi is down. The button on the plug still switches it by hand. For setups that keep working offline, see how to build a smart home without Wi-Fi.
What should I buy first?
If this is your first smart device, the smart home starter plan works out a buying order from your phones, budget and goals. For models and room-by-room ideas, see the smart plugs guide.
Sources
Last checked against the sources above: 11 October 2026.
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