How to use the electric bill splitter by appliance
- Enter your electric bill and the days in the billing period. If your bill shows the total kilowatt-hours used, enter that too.
- List your appliances with their power in watts and hours used per day. If an appliance runs on only some days, enter the days used, or leave it blank for every day.
- Read the share of the bill each appliance takes in dollars, and its energy in kilowatt-hours. If you gave the bill's kilowatt-hours, whatever the list does not explain appears as other use.
- Use Copy, Print or CSV to keep the result.
Formula
Energy (kWh) = watts x hours per day x days / 1,000
Share of the bill = appliance kWh / total kWh x bill
Average rate = bill / kWh on the bill
With the kWh from your bill, each appliance is priced at your average rate and the leftover is other use. Without it, the bill is shared in proportion among the appliances you listed, so their shares add up to the whole bill.
A 150 dollar bill and four appliances
Over 30 days, an air conditioner of 1,500 watts running 6 hours a day uses 270 kWh. A refrigerator of 150 watts running 24 hours uses 108 kWh, a water heater of 4,000 watts for 1.5 hours uses 180 kWh and lights of 200 watts for 5 hours use 30 kWh. Together that is 588 kWh.
Sharing a $150 bill in proportion gives $68.88 for the air conditioner, $27.55 for the refrigerator, $45.92 for the water heater and $7.65 for the lights. Now suppose the bill says 600 kWh. The average rate is $0.25 per kWh, so the shares become $67.50, $27.00, $45.00 and $7.50, with $3.00 left for other use.
Finding the watts and hours
Watts are usually printed on a label on the appliance or in its manual. Many labels show the highest power the device can draw. A refrigerator or air conditioner cycles on and off, so use the hours it actually runs, not 24. A plug in power meter, if you have one, gives a more reliable figure than a label.
For hours, use an honest daily average. Lights and screens vary by season, and heating or cooling can vary a lot by weather. If you are unsure, run the tool twice with a low and a high guess to see the range.
Limits of splitting a bill
Many bills have fixed charges, tiered rates or higher prices at certain hours. This tool spreads the whole bill evenly per kilowatt-hour, so it is a simple guide, not an exact accounting. For a quick cost of one appliance at your rate, use the electricity cost calculator.
Seeing a big share can point to where to save. To judge whether a new, more efficient appliance pays for itself, try the appliance replacement payback calculator. Home water use works in a similar way in the water bill calculator.
Assumptions and limits
- Every appliance draws its stated watts while it is on. Real devices often draw less, or change with load.
- The bill is spread evenly per kilowatt-hour. Fixed fees, tiers and time of day prices are not modeled.
- Cents are shared out so that the parts add up to the bill exactly.
- The example watts and hours are starting points to edit, not average values for any household.
Frequently asked questions
Why do the shares add up to the whole bill?
The tool divides the bill in whole cents and hands out any leftover cent to the appliances with the largest remainders, so the shares always match the total to the penny.
What is other use?
If you enter the kilowatt-hours from your bill, the difference between that and the listed appliances is energy the list does not explain, such as devices you forgot or standby power.
What if the listed appliances use more than my bill?
Then a watt or hour figure is too high. The tool stops and tells you, because appliances cannot use more than the meter recorded.
How do I find my average rate?
Divide the total on your bill by the kilowatt-hours it shows. The tool does this for you when you enter the bill kWh.