Router, Modem & Switch UPS Battery Runtime Calculator
Estimate how long a standard lead-acid or LiFePO4 UPS battery backup will keep your internet gateway, fiber ONT, PoE cameras, and NAS running during a power blackout.
Select your UPS model capacity and enter your total equipment wattage (e.g., 28W for ONT + Router), then click Calculate Outage Runtime.
How Network Equipment Wattage Translates to UPS Runtime
During a residential power outage, fiber-to-the-home (FTTH) central offices and hybrid-fiber-coax nodes usually stay online for 4 to 24 hours on utility generators—meaning your home internet only dies because your local Fiber ONT / Cable Modem and WiFi Router lost AC power. Because a typical modem + router stack draws only 18W to 30W, even an affordable 600VA–850VA UPS can keep WiFi and WiFi Calling alive for hours.
Typical Networking Device Power Consumption Reference
| Device Type | Average Power Draw | Peak Load | Outage Strategy Tip |
|---|---|---|---|
| Fiber ONT (Nokia / Calix / AT&T BGW320) | 7 W – 14 W | 18 W | Must be plugged into Battery+Surge outlets alongside the router |
| DOCSIS 3.1 Cable Modem (ARRIS S33/S34) | 10 W – 14 W | 18 W | Runs warm continuously; keep ventilated on battery backup |
| WiFi 6 / 6E / 7 Standalone Router | 11 W – 18 W | 24 W | Disable USB hard drives to save 5–8W during blackouts |
| 8-Port Unmanaged Gigabit/2.5G Switch | 3 W – 6 W | 8 W | Negligible draw; keeps wired workstations connected |
| 8-Port PoE+ Switch (4 Cameras + 2 APs) | 45 W – 65 W | 85 W | Place high-draw PoE NVR switches on a dedicated 1500VA UPS |
| 2-Bay to 4-Bay NAS (Synology / QNAP) | 18 W – 38 W | 55 W | Connect USB data cable from UPS to NAS for auto-shutdown at 20% battery |