Pick the appliances you use and estimate your daily and monthly bill.
UK and many EU/North American suppliers add a fixed daily supply (standing) charge on top of the per-kWh rate.
This tool estimates with an average unit price. Your real bill may differ because of tiered tariffs, seasonal adjustments and surcharges from your utility.
HVAC, kitchen, cleaning, tech and high-power categories, plus fully custom appliances.
Built-in residential rates for Hong Kong, Taiwan, the US, the UK and Japan, all editable.
Estimates what you would save each month by shifting heavy loads to off-peak hours.
Share your top energy hogs on social media or embed the calculator on your blog.
Your country and language are detected automatically; override the rate per kWh anytime.
Tap an appliance to add it, then adjust wattage, daily hours and quantity.
See daily kWh, monthly kWh and cost instantly, plus off-peak saving tips.
Open the page and start; no account, no personal data required.
All calculations are local — your usage data never leaves your device.
Traditional Chinese, English and Japanese, switched automatically.
Responsive layout with large tap targets for quick estimates on the go.
Identify the appliance that started running longer this month.
Compare old vs new wattage and estimate the payback period.
Split the bill fairly based on real usage hours per room.
See how much overnight charging saves compared with peak hours.
We use watts × hours ÷ 1000 × rate, which is a solid approximation. Real bills also depend on tiered pricing, seasonal rates and standby draw.
Yes. Enter the price per kWh from your own bill at the top of the calculator and everything updates instantly.
Time-of-use tariffs are much cheaper overnight, so moving dryers, dishwashers and EV charging often saves another 10%+.
Hong Kong, Taiwan, the US, the UK and Japan are built in; anywhere else works by typing your local rate.
No. Everything runs in your browser; only language and region preferences are stored locally.
A modern refrigerator draws roughly 100-200 watts while the compressor runs, but it cycles on and off, so real-world use is about 1-2 kWh per day, or 30-60 kWh per month.
Divide watts by 1,000 to get kilowatts, multiply by hours used per day for daily kWh, then multiply by your rate per kWh. Multiply by 30 for a monthly cost, and add any daily standing charge.
Add a few appliances and see your monthly cost and saving potential in under 30 seconds.
Daily kWh = Power (W) × Hours used per day ÷ 1000
Multiply daily kWh by 30 days and by your local rate per kWh to get the monthly cost of an appliance. This calculator totals every appliance you select and updates instantly as you change wattage, hours or quantity.
Reference residential rates for Hong Kong, Taiwan, the United States, the United Kingdom and Japan. Real tariffs vary by usage tier, season and supplier, so you can override the rate at the top of the calculator.
| Region | Currency | Rate per kWh |
|---|---|---|
| 香港 (Hong Kong) | HK$ | HK$ 1.4 |
| 台灣 (Taiwan) | NT$ | NT$ 3.52 |
| 美國 (United States) | $ | $ 0.16 |
| 英國 (United Kingdom) | £ | £ 0.2565 |
| 日本 (Japan) | ¥ | ¥ 31 |
Air conditioning, electric water heaters, tumble dryers and EV chargers often account for more than half of a household bill. The rank card in this tool shows your top three consumers instantly.
Many regions offer time-of-use tariffs with much cheaper overnight rates. Shifting laundry, dishwashing and EV charging to off-peak hours can cut another 10% or more off your bill.
Set-top boxes, consoles, routers and chargers draw power around the clock. Use switchable power strips and cut them off when you leave home.
Results are estimates for guidance only; your utility bill is the authoritative figure.