How to use the Electricity Units (kWh) Calculator
- 1. List your appliancesOne per line: name, watts, quantity, hours per day.
- 2. Enter your rateThe per-unit rate from your bill, and the days in the billing period.
- 3. See units and costA table per appliance plus total units and cost.
How electricity units are calculated
One unit on your bill is one kilowatt-hour (kWh): 1,000 watts running for one hour. For each appliance, units per day = watts × quantity × hours ÷ 1000. Multiply by the days in the billing period for the period's units, and by the rate per unit for the energy charge.
Worked example: three 75 W ceiling fans running 10 hours a day use 75 × 3 × 10 / 1000 = 2.25 kWh a day, or 67.5 units in 30 days. A 1,500 W air conditioner for 6 hours uses 9 kWh a day, which is 270 units a month. At ₹7 per unit, that is ₹1,890 for the AC alone.
Tips for accurate estimates and exam questions
- Use the wattage on the rating plate. For ACs and fridges the compressor cycles on and off, so the real average is lower than the rating.
- Tariffs in India are usually slab-based, with fixed charges and duty. Enter your effective rate for a closer estimate.
- Standby loads like set-top boxes add up over a month.
Typical basic electrical questions: find the monthly energy for a list of loads, find the cost of running a 2 kW heater for 3 hours daily, or convert joules to kWh (1 kWh = 3.6 MJ).
Frequently asked questions
What is one unit of electricity?
One unit is one kilowatt-hour: a 1,000 W load running for one hour, or a 100 W load running for ten hours.
Why is my real bill different?
Boards charge in slabs, add fixed charges, electricity duty and sometimes fuel adjustment. This tool uses one flat rate that you choose.
How do I find an appliance's wattage?
Check its rating plate or manual. For a fan regulator or inverter AC, the actual power varies with the setting.
Is this tool free?
Yes. You enter your name and WhatsApp number once to see your result, and all other Uncodemy tools then open without the form.