BYTETOOLS

Electricity Cost Calculator

Calculate what appliances cost to run: enter watts, hours per day and days per week to get kWh and cost per day, month and year, for a whole list of devices.

Appliances

$465.38
$223.38
$22.34

Columns: name, quantity, watts, hours per day, days per week, cost per year.

11.460
kWh per day
348.6
kWh per month
4,182.9
kWh per year
1,673.2
CO₂ per year (kg)
$1.95
Cost per day
$59.26
Cost per month
$711.09
Cost per year

Energy = watts × hours ÷ 1,000, giving kilowatt-hours, then multiplied by your unit rate. Part-week use is averaged across seven days, a month is taken as 365 ÷ 12 = 30.4 days and a year as 365 days. Nameplate wattage is a maximum — thermostatically controlled appliances such as fridges, freezers and heaters cycle on and off, so a plug-in energy monitor gives a truer figure. Standing charges, tiered tariffs and taxes are not included. Estimates only.

What is the Electricity Cost Calculator?

The ByteTools Electricity Cost Calculator shows what your appliances actually cost to run. Add each device with its wattage, how many hours a day it runs and how many days a week, and it converts that into kilowatt-hours and multiplies by your unit rate to give the cost per day, per month and per year.

  • Unlimited appliances with per-row annual cost
  • Quantity field for identical devices
  • Part-week usage averaged properly across the week
  • Daily, monthly and yearly kWh and cost totals
  • Optional CO₂ estimate from a grid carbon intensity you set
  • Copy or download the table as CSV — all offline in your browser

How to use the Electricity Cost Calculator

  1. 1

    Select your currency and enter the price per kWh from your latest bill.

  2. 2

    Add a row for each appliance with its wattage, hours per day and days per week.

  3. 3

    Set the quantity if you have several identical devices, such as light bulbs.

  4. 4

    Read the per-appliance annual cost and the combined daily, monthly and yearly totals.

  5. 5

    Copy the table or download it as CSV to keep a record.

About the Electricity Cost Calculator

The ByteTools Electricity Cost Calculator shows what your appliances actually cost to run. Add each device with its wattage, how many hours a day it runs and how many days a week, and it converts that into kilowatt-hours and multiplies by your unit rate to give the cost per day, per month and per year.

Because you can list several appliances at once, it is easy to see which ones dominate the bill — a 1,500 W heater running five hours a day usually costs more per year than every light in the house combined. Each row shows its own annual cost, and the table can be copied or downloaded as CSV.

Everything is calculated in your browser and nothing is uploaded, so your tariff and usage stay private. Nameplate wattage is a maximum and thermostatically controlled devices cycle, so treat the totals as estimates rather than a prediction of your bill.

Frequently asked questions

How do I calculate the cost of running an appliance?

Multiply the wattage by the hours used, divide by 1,000 to get kilowatt-hours, then multiply by your price per kWh. A 1,500 W heater run for 5 hours uses 7.5 kWh; at $0.17 per kWh that is $1.28 a day, or about $466 a year if you run it daily.

How much does it cost to run a 1500W heater for 24 hours?

A 1,500 W heater running continuously uses 36 kWh a day. At $0.17 per kWh that is $6.12 per day, so about $186 a month. Thermostats cut this substantially in practice because the element cycles off once the room reaches temperature.

Where do I find an appliance's wattage?

Look at the rating plate on the back or underside, or the manual. If only amps and volts are given, multiply them: 5 A at 120 V is 600 W. A plug-in energy monitor gives the most honest figure because it measures what the device actually draws.

Why is my actual bill higher than this estimate?

Bills include standing or daily charges, taxes and sometimes tiered or time-of-use rates that this calculator does not model. It also uses nameplate wattage, which is a maximum rather than an average. Use it to compare appliances, not to predict a bill to the cent.

How much CO2 does my electricity use produce?

Multiply your annual kWh by your grid's carbon intensity. The default here is 400 g per kWh, which is a middling figure — some grids are below 50 and others above 700, and the number changes hour by hour. Your supplier or grid operator publishes a current figure.

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