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How Much Does It Cost to Run a Cable or Fiber Modem? (2026)

A modem runs all day at 5 to 15 watts. Combined with a separate router the pair uses around 15 to 25 watts continuously, roughly 150 to 200 kWh a year.

A typical cable or fiber modem (8 W) costs $0.001 per hour, or about $1.04 per month at 24 hours a day in United States (average). Cheap to run

WattagePer hourPer dayPer monthPer year
Low (5 W)$0.001$0.022$0.65$7.88
Typical (8 W)$0.001$0.035$1.04$12.61
High (15 W)$0.003$0.065$1.94$23.65

Formula: watts ÷ 1000 × hours × price per kWh. Typical use is 24 h/day ≈ 70 kWh per year.

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How to lower the cost of running a cable or fiber modem

Frequently asked questions

How much electricity does a modem use per month?

Around 6 kWh a month at 8 watts continuous.

Is it worth turning off the modem at night?

It saves about 2 to 3 kWh a month. Most people find it not worth the hassle.

Do fiber ONTs use less power than cable modems?

Usually a little less, typically 5 to 8 watts.

Cost by region

Related appliances

Use the generic electricity cost calculator →