How Many Watts Is 30 Amps? (+Watt & Amps Calculator)

Problems will arise if you use a breaker that cannot handle the circuit’s load. Unlike a 100-200 amp service, a 30 amp breaker is not used for the whole house but for smaller household devices like a toaster, microwave, and coffee maker. 

Generally, most US households use a 120 V power supply, so 30 Amps will be 3600 watts(30×120). Given the voltage drop, which can be between 1-3%, your household wattage can range between 3492-3600 watts. Similarly, if your household has 240 V, you will have 6984 to 7200 watts.

If you have a 30 amp breaker, you should know its wattage capacity to understand which appliance will work fine with the breaker. Stick to this article till the end to find out the wattage value of 30 amps and its common applications.

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Understanding the electrical power units 

To understand how many watts 30 amps is, you must perform a few conversions and calculations with some formulas. 

These formulas will involve some units. In this section, we shall discuss some basic units to help you make the calculations easier to understand. 

Though there are multiple units, below are some standard and basic units of electrical power:

  • Volt (V): Volt is the amount of work needed to transfer the electric charge from one point to another. 
  • Current (I) or ampere (A): It is the amount of charge or electron that passes through the circuit per unit of time.
  • Resistance: It is the opposition given to the circuit’s current flow. 
  • Power (P) or Watts (W): It is the work product required and the electron number that passes through the circuit per unit of time. 
  • Watt-hour (Wh): It is the amount of energy consumed by the circuit over a given time. 
  • Decibel (dB): It is the 1/10th Bel unit used to represent the voltage, power, or current profit.  

Conversion of amps to watts

Watt Calculator

Watt Calculator


The question about how many watts are 30 amps often comes up among members new to the electrical wiring world. 

There is no exact answer to this, as the conversion of amps to watts is based on various factors. 

First, you should understand the difference between amps and watts. 

Amps or amperage is the electrical current measurement that flows through the circuit. Watts is the power or electrical energy used. 

So, the higher the amps, the higher the wattage. 

To know how many amps are 30 amps, you need to convert the amperage rating to watts. 

The formula to find out the wattage is to multiply amps and volts. 

In the United States, the standard voltage of the household circuit is 120V. 

So, 30 amps will be 30 amps x120V = 3,600 watts. 

However, only some people use 240-volt circuits, provided they have heavy-duty appliances that require more current to run safely. 

In that case, 30 amps would be 30 amps x 240V = 7,200 watts.

This conversion of the amperage rating to wattage is the general rule of thumb. 

The actual conversion and calculator depend on several factors. 

However, this formula is assumed to be the easiest and safest to receive the equal value of 30 amps. 

Calculating watts from amps

Amps Calculator

Amps Calculator


To convert watts from amps accurately, specify if the current type is direct (DC) or alternating (AC). 

If you have an alternating current, calculating watts from 30 amps will be different in both single and 3-phase systems.

Here are a few formulas:

DC: P(W) = 30A x V(V)

AC, Single phase: P(W) = 30A x PF x V(V)

AC, Three Phase, Line to line voltage: P(W) = 30A x √3 x PF x -L(V)

AC, Three Phase, Line to neutral voltage: P(W) = 30A x 3 X PF x VL-0(V)

For the alternating current, the power factor should equal the real power. 

P = I2R will be divided by the apparat power, 0 ≤ PF ≤ 1. 

Here I = 30A, R = resistance.

To calculate the wattage of 30 amps, know the voltage. 

If you use a 120V circuit, the utility company may give you 110V due to a 3% voltage drop.

If the power factor or PF is 0.5, and the circuit voltage is 110V, here are the following calculations:

Direct current or DC 

P = 30Ax 110V = 3,300W

Alternating current or AC 

Single phase: P = 30A x 0.5 x 110V AC2= 1,650W

Three Phase, Line to line voltage: AC2P = 30A x √3 x 0.5 x 110 V = 2,857.88W

Three Phase, Line to neutral voltage: P = 30Ax 3 x 0.5 x 110V = 4,950W

If you have 240V, expect 220 or 230V circuits and calculate the value. 

If you want to avoid doing the math yourself, use the calculator I provided above to solve the wattage of 30 amps at different current types and phases.

Since 120V is common in the US, I have calculated it for easy understanding. 

Importance of electrical current in determining the power consumption 

Knowing the electrical current capacity of a circuit is very important as it allows you to determine the power consumption of the connected appliances.

Based on the capacity of 30 amps, you should use appliances that consume 80% of 30 amps. 

If you have 30 amps, the appliance you connect to the circuit should consume around 24 amps. 

A 30-amp service will work fine if you keep the electrical usage within 24 amps. 

Maximum 30 amps service shave 3 to 6 circuits. One circuit will be the main power coming into your camper, and the remaining will be separate circuits. 

Heavy-duty appliances like air conditioners always have a 20 amp dedicated breaker. 

The refrigerators and microwaves also have their own 15 to 20 amps breaker. 

You can wire a coffee pot with a 30 amp service and decide to run a microwave in the same circuit. 

A coffee pot draws 6.8 amps, and a microwave draws 13.6 amps. 

Since the total amperage draw will be 20.4, below 24 amps, it will be fine. 

You can also calculate the power consumption by watts. 

As we know, 30 amps mean 3,600 to 7,200 watts. 

Here is a list of some appliances with their wattage you can use for 30 amps:

  • Clothes washer – 400 to 500 watts
  • Clothes iron – 900 to 1,800 watts
  • Hair dryer – 1,250 to 1,875 watts
  • Toaster oven – 1,230 watts
  • Microwave oven – 800 to 1,100 watts
  • Refrigerator – 725 watts
  • LCD television – 120 watts

Remember that you should use a dedicated 30 amps breaker for these appliances. 

Sometimes, you can run more than one appliance in a 30 amps circuit. 

If your 10,000 watts air conditioner draws only 6.4 amps, you can run a microwave in the same circuit that consumes only 13 amps. 

However, you can use the microwave only for 30 to 40 seconds. 

Even though you may run more than one appliance that draws less current, for example, a coffee pot, in a 30 amp circuit, it is better to avoid it. 

Suppose you keep running the microwave even after the air conditioner’s compressor has kicked in and starts drawing 18.2 amps. In that case, you will overload and trip the breaker.

What if there is a 50 amp RV but only 30 amp available?

Suppose you have a 50 amp Class A motorhome, fifth wheel, or a travel trailer, but you have an RV park that offers only 30 amp power. 

In that case, you can use a 30 to 50 amps adapter plug to give enough power to the RV.

Since you have only 30 amps to work with, you should know the power draw of the appliances and other electrical devices you use. 

It will let you understand whether you can run any 2 simultaneously.

Relation between volts, amps, and watts in electrical circuits 

Volt, amperage, and wattage are closely related to each other. 

Here are some formulas to clear the relationship between the three:

  • Amps x volts = watts
  • Watts / volts = amps
  • Watts / amps = volts

To determine the amperage rating, you must uncover the wattage and volt and divide the former by the latter. 

Multiply the voltage and amperage rating to receive the wattage. 

To calculate one value, you need the other two units. 

Multiply the voltage and current to receive the power value. If the voltage increases, your power will also increase. 

But volt-ampere is not the same as wattage. Both are power units, but the wattage is the real power equivalent to the product of voltage and current. 

The volt-ampere is the apparent power consumed and equivalent to the voltage and current multiplied by the power factor. 

In direct current, wattage = volt-ampere (VA).

In alternating current, wattage (W) ≤ volt-ampere (VA).

Final thoughts 

To know the wattage of 30 amps, understand the circuit’s voltage. You can convert the amps to watts by multiplying the amps with voltage. Since 120V is mostly used in the United States, the wattage of 30 amps is 3,600W. A 240V circuit is only used when you run heavy-duty appliances that need more electricity. In that case, 30 amps will have 7,200 watts. 

There will be a slight difference in the wattage value if you consider the current type (AC or DC). The formulas in the article can help you with it, or you can use online calculators. You should know the current capacity of 30 amps to determine the power consumption of the connected appliance. 

The article contains a list of a few devices with their required wattage. You can use them for your 30 amps circuits. The rule is to use 24 amps out of 30, following the 80% rule. It will keep things safe without any overloading and short circuits. Contact your professional to find out the wattage of your panel before you use it for your household appliances. 

What can I run on a 30 amp service?

You can run small household appliances like microwaves, toasters, and coffeemakers. You can also use slightly heavy appliances like a TV, cloth washer, and refrigerator. You should check the wattage and power consumption value before connecting.

Is 30-amp enough for an RV?

30 amp for RV is enough as many campsites with power posts with amp rating fit the reading. However, if it is insufficient, use a 50 amp plug to pair a 30 amp with a 50 amp.

What is the maximum load for 10 amps 250VAC?

You can connect multiple devices to 10 amps 250VAC, but you must ensure that the voltage, amp rating, and wattage does not exceed the load limit. For example, you can use a 1,800-watt heater, 1,600-watt vacuum cleaner, and 200-watt TV to a 10-amp 250VAC socket.

Reference: Watt Wikipedia, Amps Wikipedia.

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Arthur Smith

Howdy! I am Arthur Smith, an electrical engineer who is extremely passionate about electronics. I have lived in different parts of the US and currently reside in Wisconsin. I am one of those rare children who knew what he wanted to study and do in life right from the start. I was a curious child who wanted to know how switches work and how the AC works, and I would always observe my dad whenever he would handle the wires and fix things around the house. I currently work as an electrical engineer at a reputed company and write for this blog. And I read loads of books or play video games in my free time.

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