Energy Cost Calculator

What is an energy cost calculator?

An energy cost calculator estimates how much it costs to run electrical appliances or use natural gas in your home. By entering an appliance's power rating (watts) and the hours it operates, you can see exactly how much each device adds to your utility bill. This awareness is the first step toward reducing energy costs.

Electricity is billed in kilowatt-hours (kWh) — one kWh equals running a 1,000-watt appliance for one hour. Natural gas is typically billed per cubic meter or per kWh of energy content. Understanding these units helps you read your utility bill accurately and identify which appliances cost the most to operate.

How to calculate electricity cost

Multiply the appliance's wattage by the hours it runs per day, then divide by 1,000 to convert to kilowatt-hours. Multiply by your electricity rate to get the daily cost. For example, a 2,000-watt washing machine running for 1 hour uses 2 kWh. At $0.15 per kWh, that costs $0.30 per load.

Natural gas units

Natural gas is billed per cubic meter (m3) or per kWh of energy content. One cubic meter of natural gas contains roughly 10–11 kWh of energy, depending on gas composition and your supplier. Check your bill to confirm which unit and rate applies. Heating, hot water, and cooking are the main residential gas consumers.

How to use this tool

Select an appliance from the presets or enter a custom wattage. Set the daily usage hours and your electricity rate. The calculator shows the cost per hour, per day, per month, and per year. For natural gas appliances, switch to the gas calculator and enter your gas rate.

Energy saving tips

• Switch to LED bulbs — they use 75% less energy than incandescent bulbs and last 25 times longer.
• Unplug devices in standby mode. TVs, game consoles, and chargers draw power even when off.
• Use a programmable thermostat to reduce heating and cooling when you are away or sleeping.
• Run dishwashers and washing machines with full loads. Half-loads use almost as much energy.
• Air-dry laundry when possible — clothes dryers are among the most energy-hungry household appliances.

Worked example

A 1,500-watt space heater running 5 hours a day uses 1.5 x 5 = 7.5 kWh daily. At $0.16 per kWh that is $1.20 a day, about $36 over a 30-day month. Compare that with a 9-watt LED bulb on for the same 5 hours: 0.009 x 5 = 0.045 kWh, well under a cent a day. Ranking appliances this way shows where your bill actually comes from — heating and cooling almost always dominate.

Common mistakes

A frequent mistake is confusing power (watts) with energy (kilowatt-hours); the bill charges for energy, which is power multiplied by time. Another is using an appliance's peak rating as if it ran at full power constantly — a fridge or thermostat-controlled heater cycles on and off, so its average draw is lower. Finally, standby power adds up: devices left plugged in can quietly consume several kWh a month.

Frequently asked questions

Which household appliances use the most electricity?

Heating and cooling systems (HVAC) dominate electricity use, accounting for 40–50% of a typical home's bill. Water heaters, clothes dryers, and electric ovens are the next biggest consumers. In contrast, TVs, computers, and lighting are relatively minor consumers — though they add up due to long daily usage hours.

How do I read my electricity meter?

Digital meters display the total kWh consumed. Note the reading at the start and end of a period, and the difference is your consumption. Smart meters transmit readings automatically. If you want to measure a specific appliance, use a plug-in power meter (kill-a-watt device) between the appliance and the outlet.

How do I convert watts to kilowatt-hours?

Multiply the wattage by the number of hours used, then divide by 1,000. A 2,000-watt appliance run for 3 hours uses 2,000 x 3 / 1,000 = 6 kWh. Kilowatt-hours are the unit your utility bills, so this conversion turns a device's rating into a real cost.