How to Convert Daily kWh Into a Monthly Electric Cost

Convert one day into one month

Multiply daily kWh by the number of days in the billing period, then multiply by the price per kWh. A device averaging 2 kWh per day uses about 60 kWh in a 30-day month.

Use the actual billing period

Utility billing periods are not always exactly 30 days. Use the start and end dates shown on the bill when comparing a monitor estimate with billed usage, especially if the daily load is large.

• Use 28, 29, 30, or 31 days for a calendar month.
• Use 365 days for a simple annual estimate, or 366 in a leap year.
• Match the energy rate to the same period when prices changed midyear.

Separate steady and seasonal loads

A refrigerator may have a fairly stable daily baseline, while air conditioning, heating, dehumidification, and pool equipment change with the season. Build separate month types instead of multiplying one unusually hot or mild day across the entire year.

Know what the monitor includes

A plug-in meter records the appliance connected through it, while a circuit or whole-home monitor may include several devices. Check the measurement boundary before assigning all recorded kWh to one appliance.