{
  "id": "electricity-cost",
  "version": "cca537efb134",
  "status": "published",
  "name": "Electricity Cost Calculator",
  "question": "What does it cost to run per kWh?",
  "summary": "Computes the electricity an appliance uses in kilowatt-hours from its power and hours of use a day, and what that costs per day, month and year at a price per kWh.",
  "category": "everyday-life",
  "url": "https://www.acalculator.org/everyday-life/electricity-cost-calculator",
  "markdown": "https://www.acalculator.org/everyday-life/electricity-cost-calculator.md",
  "kind": "function",
  "method": "kWh a day = power (kW) × hours a day × how many; cost a day = kWh × price; a month = 365 ÷ 12 days; a year = 365 days",
  "assumptions": [
    "The power is the average the appliance draws while on. Appliances that cycle, such as refrigerators, draw less on average than their label.",
    "The price is a flat rate per kWh. Bills with tiers, time-of-use rates, fixed charges or taxes cost more or less.",
    "The default price is the US average residential price for July 2026, 18.31¢ per kWh, from the EIA."
  ],
  "inputs": {
    "$schema": "https://json-schema.org/draft/2020-12/schema",
    "type": "object",
    "properties": {
      "power": {
        "title": "Power",
        "description": "The power the appliance draws while on, from its label or a plug-in meter.",
        "type": [
          "number",
          "string"
        ],
        "x-quantity": "power",
        "minimum": 0,
        "maximum": 10000000
      },
      "hours": {
        "title": "Hours a day",
        "description": "How many hours a day the appliance is on.",
        "type": "number",
        "minimum": 0,
        "maximum": 24
      },
      "qty": {
        "title": "How many",
        "description": "How many of these appliances.",
        "type": "integer",
        "minimum": 1,
        "maximum": 100000
      },
      "rate": {
        "title": "Price (¢/kWh)",
        "description": "The price of electricity in cents per kilowatt-hour, from your bill.",
        "type": "number",
        "minimum": 0,
        "maximum": 1000
      }
    }
  },
  "outputs": {
    "perMonth": {
      "label": "Cost per month",
      "description": "The cost for an average month of 365 ÷ 12 days.",
      "format": "money"
    },
    "perDay": {
      "label": "Cost per day",
      "description": "kWh a day × the price.",
      "format": "money"
    },
    "perYear": {
      "label": "Cost per year",
      "description": "The cost for 365 days.",
      "format": "money"
    },
    "energyDay": {
      "label": "Energy per day",
      "description": "Power × hours a day × how many.",
      "format": "quantity",
      "unit": "kWh"
    },
    "energyYear": {
      "label": "Energy per year",
      "description": "The energy per day × 365.",
      "format": "quantity",
      "unit": "kWh"
    }
  },
  "defaultAnswer": {
    "inputs": {
      "power": 1500,
      "hours": 3,
      "qty": 1,
      "rate": 18.31
    },
    "outputs": {
      "perMonth": 25.0618125,
      "perDay": 0.82395,
      "perYear": 300.74174999999997,
      "energyDay": 16200000,
      "energyYear": 5913000000
    },
    "text": "Using 4.5 kWh a day costs $25.06 a month."
  },
  "examples": [
    {
      "given": {
        "power": 1500,
        "hours": 3,
        "qty": 1,
        "rate": 18.31
      },
      "expect": {
        "energyDay": 16200000,
        "perDay": 0.8239500000000001,
        "perMonth": 25.061812500000002,
        "perYear": 300.74175
      },
      "source": "hand calculation in content.mdx: 1.5 kW × 3 h = 4.5 kWh × $0.1831 = $0.824 a day; × 30.42 = $25.06 a month; × 365 = $300.74 a year"
    },
    {
      "given": {
        "power": 10,
        "hours": 5,
        "qty": 8,
        "rate": 15
      },
      "expect": {
        "energyDay": 1440000,
        "perYear": 21.9
      },
      "source": "hand calculation in content.mdx: 8 × 10 W × 5 h = 400 Wh = 0.4 kWh; × 365 = 146 kWh × $0.15 = $21.90 a year"
    },
    {
      "given": {
        "power": 200,
        "hours": 24,
        "qty": 1,
        "rate": 20
      },
      "expect": {
        "energyYear": 6307200000,
        "perYear": 350.4
      },
      "source": "hand calculation in content.mdx: 0.2 kW × 24 h = 4.8 kWh a day; × 365 = 1,752 kWh × $0.20 = $350.40",
      "tolerance": 1e-12
    }
  ],
  "sources": [
    "U.S. Energy Information Administration, Electric Power Monthly, Table 5.6.A: US total residential price 18.31¢ per kWh, July 2026 (released September 24, 2026). https://www.eia.gov/electricity/monthly/epm_table_grapher.php?t=epmt_5_6_a",
    "NIST SP 811 (2008), Appendix B: 1 kWh = 3.6 MJ; 1 W = 1 J/s."
  ],
  "related": [
    "btu",
    "gas"
  ],
  "changelog": []
}