How Much Electricity?
Appliance energy and cost estimator
Turn an appliance’s power rating and usage time into estimated electricity consumption and cost, so you can see what is genuinely expensive to run.
Why I made this tool
A high electricity bill rarely tells us which everyday habit caused it. I wanted a quick way to compare a heater used for one hour, a dehumidifier running overnight and a kettle used several times a day without pretending the answer is exact.
What it helps with
Estimated kWh usage and electricity cost from appliance wattage, duration, frequency and tariff.
When it is most useful
- Comparing the running cost of two appliances.
- Estimating the cost of a heater, dehumidifier or tumble dryer.
- Understanding how daily use becomes a weekly or monthly cost.
- Testing whether a small change in usage time could make a meaningful difference.
Before you start
- The wattage shown on the appliance or manual.
- How long and how often it is used.
- Your electricity unit rate if available.
How to use it
- Choose an appliance or enter its wattage.
- Enter the usage time and frequency.
- Enter your tariff or use a clearly labelled estimate.
- Calculate and compare the daily, weekly or monthly figures.
- Repeat with another appliance or a shorter usage time to test alternatives.
How to read the result
The result is an estimate based on the power and time entered. Thermostats, standby behaviour, variable power and real-world usage can make the actual figure different.
What it cannot do
- It is not a meter reading or an energy-bill forecast.
- Rated wattage may differ from average real-world consumption.
- Standing charges, tiered pricing and time-of-use tariffs require separate treatment.
Data and privacy
Frequently asked questions
Is the estimate the same as my actual bill?
No. It estimates the energy used by the appliance and does not include every part of a household bill.
Where can I find the wattage?
Check the rating label, plug, manual or manufacturer’s product page.
Why does a thermostat-controlled appliance differ?
It may cycle on and off rather than draw its full rated power continuously.