Electricity unit converter
Three conversions in one place. Watts to units, which is the arithmetic behind every figure on this site. Air conditioner tons to electrical input, which is where most household estimates go wrong. And motor horsepower to watts, which is where pump estimates go wrong. Check the result against the definition of a unit if any of it is unfamiliar.
Watts to units
The one calculation behind every figure on this site: watts × hours ÷ 1,000 = units.
Units
324 units / cycle
- Per hour of running1.8 units
- Per day at 6 hours10.8 units
- Cost at Rs 12.5/unit — light user, protected (≈150 units/month)Rs 4,050
- Cost at Rs 27.5/unit — average household (≈250 units/month)Rs 8,910
- Cost at Rs 36/unit — heavy summer month (700+ units)Rs 11,664
Rupee figures are the marginal cost of these units on top of what you already use. They are illustrative — the tariff table printed on your own bill is authoritative.
Air conditioner tons to watts
A ton describes cooling output, not electrical input. Input depends on efficiency, so this gives a range rather than one number.
- Cooling output5.28 kW
- Electrical input, efficient unit1,465 W
- Electrical input, older unit2,029 W
Motor horsepower to watts
Horsepower is shaft output. The socket sees more, because the motor is not perfectly efficient — which is why a 1 HP pump is not a 750 watt load.
- Shaft output746 W
- Electrical input, good motor877 W
- Electrical input, older motor1,036 W
Watts × hours ÷ 1,000
A watt is a rate and a unit is a quantity. Multiplying the rate by the hours it ran, then dividing by a thousand, converts one into the other. That is the whole calculation, and it is the only one your bill's energy charge is built on.
The subtlety is not in the arithmetic but in the hours. A refrigerator is switched on for 24 hours a day and its compressor runs for perhaps 13 of them, and using the wrong figure produces an answer that is almost twice reality.
Why tons need a range, not a number
A ton of refrigeration is about 3.517 kW of cooling delivered. How much electricity it takes to deliver that depends on the machine's coefficient of performance, which for equipment sold in Pakistan sits roughly between 2.6 and 3.6.
So a 1.5 ton unit is somewhere around 1,450 to 2,000 watts of input. An efficient inverter unit at part load falls well below that range; an old fixed-speed unit against a 45 °C afternoon sits at the top of it.
Why a 1 HP pump is not a 750 watt load
Horsepower describes shaft output — the mechanical work leaving the motor. Getting that work out requires more electrical input, because the motor loses energy to heat, friction and magnetising current.
Small motors of the kind used in domestic water pumps run roughly 72 to 85 per cent efficient, so a 1 HP pump draws somewhere near 900 to 1,050 watts. Treating the nameplate horsepower as the electrical load understates a pump's contribution to the bill by a fifth or more.
Frequently asked questions
How many watts is one unit of electricity?
A unit is not a wattage — it is 1,000 watts sustained for one hour, or any equivalent combination. A 100 watt load for ten hours and a 2,000 watt load for half an hour are both one unit.
How do I convert my monthly bill units into a daily figure?
Divide the units on the bill by the number of days in the billing cycle, which is the gap between the two reading dates rather than a calendar month. A 30-day cycle at 450 units is 15 units a day.
Why does the converter give a range for air conditioners and pumps?
Because tons and horsepower describe output, not electrical input, and the conversion depends on the efficiency of the specific machine. A single number would be a false precision — the rating plate on your own equipment is the accurate figure.
Is a kVA the same as a kW?
No. kW is real power doing useful work; kVA is the apparent power the supply must provide. They are equal only at a power factor of 1, which is true of heaters and kettles but not of motors.
Related
Conversions are exact; the efficiency assumptions are not. The watts-to-units calculation is arithmetic and always correct. The ton and horsepower ranges depend on the specific machine, and the rupee figures use illustrative slab rates. Your own appliance rating plate and the tariff table printed on your bill are the authoritative sources.