kW To Amps Calculator: Convert Killowatts To Amps (+3 Examples)

One of the most frequently needed electricity conversions is kW (kilowatts) to Amps.

  • kW is a unit of measure of electrical power (wattage).
  • Ampere (A) is a unit of measure of electrical current (amperage).

To convert kW to Amps, we can use the equation for electrical power:

Power (kW) = I (A) * V (V)

You can use this kilowatt to amperes converter. Below you will find 3 examples of a kW to Amps conversion for:

  1. 4 kW central air conditioner (220 V).
  2. 1 kW washing machine (220 V).
  3. 36 kW tankless electric water heater (240 V).

kW To Amps Calculator


Using the calculator, we have calculated a kW to Amps table:

Power (kW) Voltage (220 V) Amperage (A)
1 kW to Amps: 220 V 4.55 Amps
2 kW to Amps: 220 V 9.09 Amps
4 kW to Amps: 220 V 18.18 Amps
6 kW to Amps: 220 V 27.27 Amps
9 kW to Amps: 220 V 40.91 Amps
18 kW to Amps: 220 V 81.82 Amps
27 kW to Amps: 220 V 122.73 Amps
36 kW to Amps: 220 V 163.64 Amps
45 kW to Amps: 220 V 227.27 Amps

Example 1: How Many Amps Does 4 kW Central AC Unit Draw?

For example, let’s take a 36,000 BTU central air conditioner with a power output of 4 kW. The electrical circuit can provide 220 V voltage. How many amps does the 4 kW AC unit draw? Let’s use the kW to Amps calculator:

We can see that the 4 kW air conditioner needs 18.18 amps to function properly.

Example 2: 1 kW Washing Machine To Amps

Most washing machines draw about 1,000 W or 1 kW of electrical power. You don’t need upgrades to your electrical circuit for an average washing machine. Here is how many amps it draws:

1 kW washing machine needs about 4.55 Amps to run.

Example 3: 36 kW Electrical Tankless Water Heater

Tankless water heaters are notorious for needing a huge amount of electrical current (amps). For example, you have 9 kW, 18 kW, 27 kW, and even 36 kW tankless water heaters that run on electricity. Usually, they run on 240 V and can reach up to 200 amps.

For this example, let’s take a bigger 36 kW tankless water heater on 240 V potential:

As you can see, 36 kW converts to 150 amps. This is some serious amperage; for such a device, you would need 4 x 40 A breakers.

This conversion can be quite useful for a number of different applications. For example, if you have ever wondered how long does it take to charge a Tesla Model 3 (check here), you will have to think about kW as well as amps.

If you have any questions about kW to amps calculation, you can pose them in the comments below.

26 thoughts on “kW To Amps Calculator: Convert Killowatts To Amps (+3 Examples)”

  1. I understand Volts x Amps = Watts.
    i Solar panel giving 300watta @ 6 Volts =50Amps (A big cable) Obviously 300W Devided by 230= 1.3 Amps, What percentage of power will I loose passing through the Inverter?

  2. I’ve measured a total KW load of 8.94 on our combined 120/220 volts (220 water heater) on our 100 amp service. Using the Calculator for 120v it says 75 Amp. We are looking at a 19KW – 51 Amp auxiliary generator. Will this work or will there be issues due to the 51 Amp rating of the generator?

    • Hello Richard, the new 19kW – 51 Amp generator has high voltage. 19,000W / 51A = 373V. If it can put out 19 kW and has proper voltage reduction to 220V or 120V, it shouldn’t be a problem to power an 8.94 kW water heater.

      • Bonsoir à tous.
        Après un relevé de charge dans une institution, on a trouvé 158 Ampères pour tous les appareils.
        Combien faut-il de Kw pour faire fonctionner ces appareils ? A noter que tous les appareils se fonctionnent sur une tension de 120 volts. Mais, ils consomment en général 158 Ampères.
        Merci pour vos réponses

        • Hello Schello, French is not our first language but Google Translate will serve well here. You have 158 amps at 120V. Here’s how you calculate the wattage: Wattage = 158 amps x 120V = 18,960 watts. This is 19 kW. Merci beaucoup.

    • Hello FM, that’s correct. It’s always best to use the basic units (W, A, V) but we used kW to better illustrate the kW to amps conversion. In the calculation, we do use the 1 kW = 1,000 W conversion.

  3. I understand that the calculator is for basically using Ohms law for restrictive loads but how would one calculate for inductive loads like pool pump or well point motors. What wold the formula for that be?
    Thanks in advance


    • Hello Michael, you’re correct; the Ohms law is the basic equation. Inductive loads like pool pumps that use 3 phase current? Sure. The equation for 3 phase current is I (Amps) = 1000 x kW / (√3 x VL x P.F.); where VL is the RMS value of the applied line voltage and P.F. is the power factor of the load. Hope this is what you were looking for.

  4. Hi there
    We live in the UK and are wanting to install an Endless swim pool in our redundant double garage. We are told that the pool with its heater, fastlane unit and lights etc require 60Amps. The supply to our property is governed by a 100Amp fuse and then split between the garage and the house. Our current domestic usage averages at about 320KWh a month over a year.
    Is the installation of the pool viable. What split do you think we should make between the garage/pool and the house? Regards Peter

    • Hello Peter, the electric installations seem alright, we have talked about 60 amp wire sizes and fuses here. Now, the 60 Amp current will deliver (at 220V) 13.2 kW of power. The pool should get the bulk of the power when needed (large enough wires and fuses are required here) and you can split the rest to the garage.

      The problem here is that the endless swimming pool requires high wattage for a limited time (maybe 2-4 hours per day), and you don’t really need that immense wattage during the rest of the day. It would make sense to minimize the garage amp draw during the time you use the endless swimming pool.

  5. Europe has 400V 3 phase outlets. Can you please edit the calculator to cover this incidence? I know, I can do the calculations elsewhere but I’d gladly bookmark and share this tool for my fello EV owners

    • Hello Csaba, oh that’s a nice insight. Sure, we have extended that voltage slider to 400V. You can easily calculate the amps from kW for 400V voltage now. Thank you for the advice.

  6. On a good day our laser machines are using up to 475 kWh
    How can I use this to determine how many amps I am drawing.
    We have only 400 amps available and I’m trying to determine how many more machines I could power.


    • Hi Richard, that’s a huge wattage. So, your the laser machine uses up to 475 kW; to calculate the amps, you need to know the voltage. At 220V voltage, that would be over 2000 amps. You are probably using 3 phase current with 480V voltage; you can use this equation for calculating the amps P (kW) = (I (Amps) × V (Volts) × PF × 1.732) ÷ 1,000 or you can consult our 3-phase power calculator here.

      Here is how you set the equation in your case: Amps = (475 kW × 1000) / (480 Volts × PF × 1.732). If we presume the PF (Power Factor) is 1, you would need 571 amps to get 475 kW of power. With 400 amps, you will get 333 kW output. Hope some of this helps.


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