One unit of electricity is one kilowatt-hour: 1,000 watts running for one hour. To find the units an appliance uses in a month, multiply its watts by the hours it runs each day and the days in the month, then divide by 1,000. A 1.5 ton inverter AC averaging 1,000 W for 8 hours a day uses 1,000 x 8 x 30 ÷ 1,000 = 240 units a month.
Pick your appliances above, set how many you have and how long they run, and the calculator adds up the units and estimates the bill from them. The watts are typical figures, so change them to match the rating plate on your own appliances.
How to calculate units of electricity consumed
The formula is the same for every appliance:
Units per month = watts x number of appliances x hours a day x days ÷ 1,000
- A ceiling fan of 80 W running 12 hours a day for 30 days: 80 x 12 x 30 ÷ 1,000 = 28.8 units.
- Eight 12 W LED bulbs for 6 hours a day: 12 x 8 x 6 x 30 ÷ 1,000 = 17.3 units.
- A 1,000 W iron used half an hour a day: 1,000 x 0.5 x 30 ÷ 1,000 = 15 units.
If a label shows amps instead of watts, multiply the amps by 230 volts to get watts. A 5 amp load is about 1,150 W. Units on your bill are the same as kWh, so a "kWh to unit" conversion is one to one.
Typical wattage of home appliances in Pakistan
These are the starting figures in the calculator. Real models vary, so the rating plate on your appliance is the better guide.
| Appliance | Watts | Hours a day | Units a day | Units in 30 days |
|---|---|---|---|---|
| Ceiling fan | 80 | 12 | 0.96 | 28.8 |
| DC inverter ceiling fan | 35 | 12 | 0.42 | 12.6 |
| Pedestal fan | 60 | 8 | 0.48 | 14.4 |
| LED bulb | 12 | 6 | 0.07 | 2.2 |
| LED tube light | 20 | 6 | 0.12 | 3.6 |
| Energy saver (CFL) | 25 | 6 | 0.15 | 4.5 |
| Refrigerator | 150 | 10 | 1.50 | 45.0 |
| Inverter refrigerator | 100 | 10 | 1.00 | 30.0 |
| Deep freezer | 200 | 12 | 2.40 | 72.0 |
| Inverter AC 1 ton | 700 | 8 | 5.60 | 168.0 |
| Inverter AC 1.5 ton | 1,000 | 8 | 8.00 | 240.0 |
| Inverter AC 2 ton | 1,400 | 8 | 11.20 | 336.0 |
| Non-inverter AC 1 ton | 1,200 | 8 | 9.60 | 288.0 |
| Non-inverter AC 1.5 ton | 1,800 | 8 | 14.40 | 432.0 |
| Air cooler | 150 | 10 | 1.50 | 45.0 |
| LED TV | 80 | 5 | 0.40 | 12.0 |
| Laptop | 50 | 6 | 0.30 | 9.0 |
| Desktop computer | 150 | 5 | 0.75 | 22.5 |
| Wi-Fi router | 10 | 24 | 0.24 | 7.2 |
| Mobile charger | 10 | 3 | 0.03 | 0.9 |
| Water motor 1 hp | 750 | 1 | 0.75 | 22.5 |
| Water motor 0.5 hp | 375 | 1 | 0.38 | 11.3 |
| Iron | 1,000 | 0.50 | 0.50 | 15.0 |
| Washing machine (twin tub) | 400 | 1 | 0.40 | 12.0 |
| Microwave oven | 1,200 | 0.25 | 0.30 | 9.0 |
| Electric kettle | 1,500 | 0.20 | 0.30 | 9.0 |
| Electric geyser | 2,000 | 2 | 4.00 | 120.0 |
| Electric room heater | 1,000 | 4 | 4.00 | 120.0 |
| Water dispenser | 100 | 10 | 1.00 | 30.0 |
For a refrigerator, freezer or AC the watts shown are while the compressor runs, and the hours are the hours it actually runs, not the hours it is switched on. A fridge compressor typically runs 8 to 12 hours out of 24.
Inverter AC power consumption
One ton of cooling is 12,000 BTU per hour, about 3.5 kW of heat removed. A fixed speed (non-inverter) AC with a typical efficiency ratio of 3 draws about 1.2 kW per ton while the compressor runs: roughly 1,200 W for 1 ton and 1,800 W for 1.5 ton.
An inverter AC slows its compressor once the room is cool, so its average draw is much lower. A study of Pakistan's cooling needs published in 2022 quotes K-Electric data of about 12 units a day for an average 1.5 ton inverter AC. That matches about 1,000 W over 12 hours, which is the figure we use.
| AC, 8 hours a day for 30 days | Watts | Units a month |
|---|---|---|
| Inverter 1 ton | 700 | 168 |
| Inverter 1.5 ton | 1,000 | 240 |
| Non-inverter 1.5 ton | 1,800 | 432 |
On a very hot afternoon, or with the thermostat set at 18°C, an inverter AC runs close to full power and uses more. Setting it at 26°C keeps it in its low power range for longer.
Worked example: a summer month in Lahore
This is the example loaded in the calculator: 4 ceiling fans for 12 hours, 8 LED bulbs for 6 hours, a fridge, a 1.5 ton inverter AC for 6 hours, a TV, a 1 hp water motor for an hour and an iron for half an hour, over 30 days.
| Appliance | Units a month |
|---|---|
| Inverter AC 1.5 ton | 180.0 |
| 4 ceiling fans | 115.2 |
| Refrigerator | 45.0 |
| Water motor | 22.5 |
| 8 LED bulbs | 17.3 |
| Iron | 15.0 |
| LED TV | 12.0 |
| Total | 407 |
With the current adjustments an unprotected 3 kW home using 407 units pays about Rs 23,102, because every unit is charged at the 401 to 500 slab rate of Rs 38.95. At 399 units the bill would be about Rs 21,139. Ironing for 15 minutes a day instead of 30 saves 7.5 units and brings the home back under 400. Watch the slab limits at 200, 300, 400 and 500 units: the calculator warns you when you are just over one.
UPS and inverter losses
A home UPS does not make electricity. It stores it in batteries and gives back less than it took. Lead-acid batteries, the charger and the inverter together commonly lose 25 to 40% of the energy that passes through them.
If a UPS runs 300 W of fans and lights for 3 hours a day during load shedding at 70% efficiency, recharging it costs about 11.6 extra units a month. Tick the UPS option to add this. A solar system with batteries has the same kind of loss, which the solar system calculator allows for.
The bill estimate uses the NEPRA uniform tariff, the current fuel and quarterly adjustments, the FC surcharge, electricity duty and 18% GST, the same way as our electricity bill calculator. Your meter is the final word: compare the total with the units on your bill and adjust the hours until they match.
Electricity usage questions
How many units does a fan use in a month?
A normal 80 W ceiling fan running 12 hours a day uses 28.8 units in 30 days. Four such fans use about 115 units. A DC inverter fan of about 35 W uses 12.6 units for the same hours, less than half, which is why they pay back quickly in homes near a slab limit.
How many units does a 1.5 ton inverter AC use?
About 1,000 W on average, so 8 hours a day uses 8 units and 240 units in 30 days. A non-inverter 1.5 ton AC draws about 1,800 W while the compressor runs, which is 432 units for the same hours. For one appliance on its own, the watt to unit calculator does the sum.
How many units does a fridge use?
A typical fridge uses about 1 to 1.5 units a day, which is 30 to 45 units a month. Its compressor draws around 100 to 150 W but switches on and off, running about 8 to 12 hours out of 24. Older fridges, and fridges in hot kitchens, use more. An inverter fridge usually uses less.
How many units does an electric geyser use?
A 2,000 W electric geyser uses 2 units for every hour its element is on. Two hours a day adds 120 units a month, which is enough to push many homes into a higher slab. A timer so the element runs only before you need hot water keeps this down.
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Last reviewed 9 October 2026. Results are estimates; official notices always take precedence.