AC Bill Calculator
(Units and Cost From the Star Label or Watts)
Enter the kWh per year from the AC's star label, or its power input in watts, with your hours and electricity rate to see units and cost.
What do you know about the AC?
Printed on the star label. It assumes about 1,600 hours of cooling a year
From your bill, in your currency
AC Running Cost
💡 Formula Guide
This AC bill calculator works out how many units an air conditioner uses and what it costs to run. Use the kWh per year printed on India's BEE star label, or the power input in watts from the spec sheet if your AC has no label.
From the Star Label
Down To Earth explains that the label's yearly figure assumes the AC runs about 1,600 hours a year for cooling. An AC labelled 900 kWh a year therefore averages 900 ÷ 1,600 = 0.5625 units an hour.
| Usage | Units | Cost at 8 per unit |
|---|---|---|
| Per hour | 0.56 | 4.50 |
| Per day (8 hours) | 4.5 | 36 |
| Per month (30 days) | 135 | 1,080 |
| Per year (6 months) | 810 | 6,480 |
A lower kWh-per-year figure on the label means a cheaper AC to run. The calculator takes the rate as a number in your currency, so it works for any tariff.
From the Power Input in Watts
An AC with a 1,500 W power input running at full load uses 1.5 units an hour. For 8 hours a day over 30 days that is 360 units, or 2,880 at 8 per unit. That is the upper limit: once the room is cool the compressor slows or cycles off, so real use is lower. If you have measured or know your average load, enter it.
For your whole bill, use the Electricity Bill Calculator. To compare with an air cooler, see the Air Cooler Electricity Calculator.
How to Use the AC Bill Calculator
- Choose what you know: Pick the star label's kWh per year, or the power input in watts from the spec sheet.
- Enter the figure: Type the label's annual kWh, or the watts and the average load.
- Enter your usage: Type hours per day, days per month and months of use per year.
- Enter your rate: Type the price of one unit from your electricity bill.
Frequently Asked Questions
How many units does an AC use per hour?
Divide the kWh per year on its BEE star label by 1,600, the hours of cooling the label assumes. An AC labelled 900 kWh a year averages 0.56 units an hour. From the spec sheet, power input in watts ÷ 1,000 is the most it draws per hour.
How do I calculate my AC's monthly bill?
Multiply units per hour by hours per day, days per month and your rate. At 0.5625 units an hour, 8 hours a day for 30 days is 135 units; at 8 per unit that is 1,080 a month.
What does the kWh per year on the star label mean?
It is the electricity the AC uses in a year of about 1,600 hours of cooling under the label's test conditions. Comparing that number between models shows which one costs less to run.
Why does my AC use more than the estimate?
A lower set temperature, hotter weather, a sunny or poorly sealed room and dirty filters all make the compressor work harder than the test conditions behind the label.
Is an inverter AC cheaper to run?
An inverter AC slows its compressor once the room is cool instead of switching it on and off, so it usually draws less than its rated power. The label's kWh per year already reflects this, which is why the label method suits inverter models.
How many units does a 1.5 ton AC use?
It depends on the model's efficiency, so check its label. A 1.5 ton AC labelled 900 kWh a year averages about 0.56 units an hour; one labelled 1,200 kWh averages 0.75.
Formulas and worked examples checked in October 2026. The 1,600-hour basis of the BEE label is from Down To Earth, checked October 2026.