Why use an electricity cost calculator?

For appliances like air conditioners, heaters, dehumidifiers, gaming PCs, or home servers, it is often hard to guess the real running cost.

This tool helps you estimate cost using just four inputs:

  • Power consumption (W)
  • Hours used per day
  • Days used per month
  • Electricity price per kWh

How it works

The calculation is straightforward:

  1. Watts ÷ 1000 = kW
  2. kW × hours per day = daily usage (kWh)
  3. Daily usage × number of days = monthly usage (kWh)
  4. Monthly usage × electricity price = estimated monthly cost

It also shows daily cost, monthly cost, and yearly cost, which makes it useful when comparing appliances.

Example

Electric heater

  • Power: 1500W
  • Usage: 4 hours/day
  • Days: 30
  • Electricity price: 150 KRW/kWh

→ Daily usage: 6kWh
→ Monthly usage: 180kWh
→ Estimated monthly cost: 27,000 KRW

Good use cases

  • Estimate air conditioner or heating cost
  • Calculate home lab / server electricity usage
  • Compare the operating cost of multiple appliances
  • Check whether a device is worth running every day

FAQ

Why is the estimate different from my actual bill?

Real electricity bills often include more than just energy usage, such as base fees, taxes, and progressive pricing. Use this tool as a quick estimate for a single appliance or usage pattern.

What is the difference between W and kW?

1000W equals 1kW. If your appliance label says 800W or 1500W, divide by 1000 to convert it into kW.

Can I use this to compare appliances?

Yes. Enter each appliance one by one and compare the monthly cost to see which one uses more electricity.