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A UPS for your router and modem

Most outages are short. A small UPS can keep the modem and router running through them, so Wi-Fi calling, work, and internet-connected alarms stay connected as long as the battery lasts and your provider's network stays up.

What a modem and router actually draw

A cable or fiber modem and a home Wi-Fi router together usually draw somewhere around 10 to 30 watts. Check the power adapters: each lists its output in volts and amps, and volts times amps is the most that adapter can supply. Real draw is usually well below that, so it is a generous estimate. Mesh systems add several watts per unit, and you only need to back up the ones that carry the core of the network.

How long it will run

UPS units are sold by VA and watts, but runtime depends on the battery and the load. Find the runtime chart in the manual or on the maker's site and read it at your load, not at full load. A unit that gives a few minutes at full load can often run a light load like this much longer, and the chart tells you how long. If you want hours instead of minutes, a portable power station is the better tool.

What to check before you buy

• Enough battery-backed outlets for the modem, the router, and anything else on the network path, such as a switch or the fiber box from your internet provider. Some outlets on a UPS are surge-only and turn off in an outage.
• Outlet spacing that fits bulky power adapters.
• Line-interactive units (often listed with AVR) can correct moderate brownouts without switching to the battery. Pure sine wave output matters more for desktop computers than for small adapters like these.
• A replaceable battery. UPS batteries wear out and usually need replacing after a few years.

When the outage takes your provider down too

A UPS keeps your equipment on, but it cannot keep your internet provider's network up. In a long, widespread outage the connection can drop even while your router stays lit. A phone hotspot is the fallback for that case, if cell service is still up. For longer outages at home, see the battery backup, UPS, and generator guide.

Questions

Can I plug the modem and router into a surge protector instead?

A surge protector helps with voltage spikes, but it has no battery, so everything plugged into it still shuts off when the power goes out. A UPS protects against surges and keeps its battery-backed outlets on until the battery runs down.

Do I need a big UPS for this?

Usually not. A modem and router are a light load, so a small UPS covers them. Buy for the battery-backed outlets you need and the runtime at your load, not for the biggest VA number.

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More guides

• Battery backup, UPS, and home generators

  Which of the three fits your outage, and how to size it from the load.

• Running a refrigerator on a portable power station

  Check the startup surge and the watt-hours before the outage, not during it.

• Standby vs portable generators for home backup

  How each connects to the house, what it needs installed, and the safety rules.