kWh Cost Per Month

Cost = W × hr/day × 30 / 1000 × $/kWh.

Inputs

US avg ~$0.16. CA: $0.30+. TX: $0.12.

Result

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General calculation reads

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How to use this calculator

  • Enter wattage (label or kill-a-watt meter).
  • Hours used per day.
  • Your local rate.

About this calculator

Cost = (watts × hours per day / 1000) × days × $/kWh. US average rate ~$0.16/kWh in 2025. A 200W device run 8 hrs/day: 1.6 kWh/day × 30 days × $0.16 = $7.68/month. Refrigerator: ~$10-15/mo. Always-on plasma TV (or "phantom" loads): $1-3/mo each, adds up to $200+/year across a typical home.

Frequently asked

Where to find wattage?+
Device label, manual, or measure with Kill-A-Watt meter ($25). Many "off" devices still draw 1-5W.
Phantom load?+
Always-on devices (TV standby, chargers, smart speakers) collectively draw 30-100 W in typical home. $40-150/year.
Tier rates?+
Many utilities have tiered pricing — first 500 kWh/mo cheap, above more expensive. Calc uses flat rate; check your bill.
EV charging?+
Tesla 100 kWh battery × $0.16 = $16 for full charge. Cheaper at home overnight than gas station.
Solar offset?+
Net-metering: solar production credits against grid usage. Calc shows gross consumption.

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