How the bill is estimated
For each appliance the tool works out watts × number × hours a day ÷ 1000 to get daily kWh. It adds them up, multiplies by the days in the bill and by your price per unit, and adds any fixed charges you enter.
Reading the result
- Check the label or the manual for the real wattage of each appliance.
- The appliances that use the most units are listed first, so you can see where to save.
- Taxes and slab prices vary by country. Use the sales tax calculator if tax is added to your bill, and the percentage calculator to compare two months.
Frequently asked questions
How do I calculate electricity units?
Multiply watts by hours of use, divide by 1,000 to get kWh (units), then multiply by the number of days. A 75 W fan used for 10 hours a day uses 0.75 units a day, about 22.5 units in 30 days.
What is a kWh or one unit?
One kilowatt-hour (kWh) is the energy used by a 1,000 W appliance running for one hour. It is what your meter counts and what your bill charges for.
Why is my real bill higher than the estimate?
The bill may include slab rates (a higher price per unit as use rises), taxes, fuel adjustments and fixed charges. Enter your average price per unit and put the extras in the fixed charges box.
How do I deal with a fridge or an air conditioner that cycles on and off?
Their compressor runs only part of the time. Enter the hours a day it is really running, for example 8–10 hours for a fridge and fewer for an AC with a thermostat.
How can I lower my bill?
Use LED bulbs, set the AC to 24–26 °C, service it regularly, and turn off standby devices. The list of top appliances in the result shows where the units go.