How a unit of electricity is counted
One “unit” on an Indian electricity bill is one kilowatt-hour (kWh): a 1,000-watt appliance running for one hour, or a 100-watt one running for ten. So the maths is simple: watts × hours a day × days ÷ 1,000 = units. A 75 W ceiling fan running 10 hours a day uses 0.75 units a day, about 22 units a month.
Some appliances do not run at full power all the time. A refrigerator’s compressor switches on and off, so its label rating overstates the real use; that is why the list starts it at an average of about 55 W over 24 hours (roughly 1.3 units a day for a double-door fridge). Inverter ACs also slow down once the room is cool. If your appliance has a BEE star label, it prints the expected units per year — divide by 365 and by 24 to get an average wattage for this calculator.
Why your real bill can be higher
Electricity boards in India use slabs: the first units are cheaper and the rate rises as you use more. On top come a fixed charge, electricity duty and sometimes a fuel adjustment charge. The simplest fix is to type your average rate: the total of your last bill divided by the units billed. Several states bill every two months, so set “days in the bill” to 60 to compare like for like.
What usually costs the most
- Air conditioners in summer — often half the bill. Each degree higher on the thermostat saves a few percent; 24–26 °C is comfortable for most people.
- Geysers and induction cooktops draw 1,800–2,000 W, so even 30 minutes a day adds up.
- Fans and lights are small one by one but run for many hours. BLDC fans use less than half the power of regular fans.
- Water pumps left on too long, and old refrigerators with worn door seals.
Buying new? Compare yearly units, not price alone
A 5-star appliance can cost more at the shop and still be cheaper over five years. Use the yearly units on the star label, multiply by your rate and by the years you plan to keep it, and add that to the price before you compare models.
Questions
How many units does a 1.5 ton AC use?
A 1.5 ton inverter split AC typically draws 0.9 to 1.3 kW on average once the room is cool, so about 1 unit per hour. Eight hours a night for 30 days is around 240 units. Non-inverter models and very hot rooms use more.
How do I find my rate per unit?
Divide the total amount on your electricity bill by the units billed. That average already includes slabs, fixed charges and duty, so it gives a realistic cost per unit.
Does a refrigerator really run 24 hours?
It is switched on all day, but the compressor runs only part of the time. A double-door fridge typically uses 1 to 1.5 units a day, which is why the calculator uses an average of about 55 W.
Do phone chargers left plugged in use electricity?
Very little: modern chargers draw well under 1 W with no phone attached. Set-top boxes, old TVs on standby and Wi-Fi routers use more because they stay on all day.
Sources
Last checked 2026-11-11. Free to use; please check important details before you rely on them.