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Electricity Cost Calculator Tool

Calculate electricity costs instantly with 30 appliance presets, multi-device totals, and replacement savings comparison.

Last updated: 2026/10/16 Calculator Feedback & bug reports
Input
hours/day
days/month
Electricity Rate
JPY/kWh
Electricity Rate
JPY/kWh
Input
Old Appliance
New Appliance
Usage Conditions (shared)
hours/day
days/month
Electricity Rate
JPY/kWh
Purchase Price of New Appliance (optional)
JPY

* Electricity costs are estimates. Actual costs vary by contract plan and usage. Rates are based on approximate Tier 3 pricing for each utility provider.

How to Use

1

Choose a Calculation Mode

Select from "Basic", "Multi-Appliance", or "Replacement" tabs depending on your needs.

2

Enter Appliance Details

Select an appliance preset to auto-fill power consumption and usage time. Choose a utility provider to auto-set the rate. All values can be manually adjusted.

3

View Real-time Results

Costs are calculated in real-time as you type. In Multi-Appliance mode, a pie chart shows the cost breakdown. Use the copy button to save results to clipboard.

About Electricity Cost Calculator

A web tool that calculates electricity costs from appliance power consumption. Built-in presets for 30 appliances and 10 Japanese utility providers. Supports multi-appliance totals and replacement comparison. All processing is done in your browser - no data is sent to any server.

Features

  • 3 Calculation ModesBasic calculation, multi-appliance totals, and replacement comparison. Choose the mode that fits your needs.
  • 30 Appliance PresetsPre-configured settings for common appliances like AC, refrigerator, and hair dryer. One-click input.
  • Utility Provider RatesBuilt-in rates for 10 Japanese utility companies. Get accurate calculations for your region.
  • Pie Chart VisualizationIn multi-appliance mode, see cost breakdown by appliance in a pie chart. Easily identify where to save.

Use Cases

  • Find out monthly air conditioner electricity cost
  • See a breakdown of household electricity costs by appliance
  • Calculate savings from replacing an old appliance
  • Estimate electricity costs for a new apartment
  • Determine if upgrading to energy-efficient appliances pays off

FAQ

How is electricity cost calculated?
Power(W) / 1000 x Usage Time(h) x Electricity Rate(JPY/kWh). For example, a 500W air conditioner used for 8 hours at 34.72 JPY/kWh costs 500/1000 x 8 x 34.72 = 138.9 JPY per day.
What electricity rate should I use?
Select your utility provider from the preset list. The default is the national average of 34.72 JPY/kWh. For more accuracy, check your electricity bill for the exact rate.
Where can I find the power consumption of my appliance?
Check the nameplate on the back or bottom of the appliance, the user manual, or the manufacturer's website. Preset values are general estimates.
How many appliances can I add in multi-appliance mode?
Up to 20 appliances can be added. Register all major household appliances to see your total electricity cost breakdown.
What is the payback period in replacement comparison?
It shows how long it takes for the electricity savings to cover the purchase price of a new energy-efficient appliance. For example, if a new fridge saves 10,000 JPY/year and costs 50,000 JPY, it pays for itself in about 5 years.
Why do AC cooling and heating use different power?
Heating typically requires more energy because the temperature difference between outdoors and the desired indoor temperature is larger in winter. Heating power consumption is generally 1.2-1.5x that of cooling.
Should I calculate refrigerator usage as 24 hours?
Yes, refrigerators run 24/7, but the compressor doesn't run constantly. The preset 30W represents average power consumption calculated from annual energy consumption.
Is my data saved?
Only the utility provider and rate settings are saved in your browser's local storage for convenience. No other data is sent to or stored on any server.
Can I use this on my phone?
Yes, it works on all devices including smartphones, tablets, and PCs with a mobile-optimized layout.
When were the utility rate presets last updated?
The rates are based on 2025 Tier 3 pricing for each utility provider. Rates may change, so check your provider's website or electricity bill for the most accurate values.

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