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How Many Amps Does a Microwave Use?

The microwave oven is a widely used kitchen appliance designed to quickly cook various types of food. Unlike gas cooking, the microwave utilizes advanced features, internally cooking food by creating vibrations in its molecules. This process generates heat using microwaves, improving food quality and allowing for rapid reheating. Despite its common usage, users often have questions about microwave ovens.

In response to these common inquiries, we conducted research to address the most popular questions regarding microwave ovens. This article delves into topics such as the actual amperage used by a microwave oven, providing practical formulas for calculating amperage. Beyond amperage, the article explores solutions for determining the optimal and ideal breaker size for a microwave oven. Finally, we comprehensively discuss a few helpful techniques to conserve energy while using a microwave oven. Let’s begin by examining the energy or amperage consumption of the microwave oven.

How Many Amps Does a Microwave Use?

There are various categories of microwave devices available in the market. However, the household microwave’s ampere consumption generally relies on the energy or power needed for its operation. Typically, the power falls within the range of 600 to 1200 watts. Therefore, after computing the current, the average is around 7 to 8 amps when using the standard United States voltage of 120V. Conversely, in regions like Asia and Europe, which follow a different standard of 230 volts, the power source preference is different. In such cases, the current drawn by the circuit varies. Compared to the 120-volt system, the 230-volt supply system draws half the current or amps.

The microwave oven’s amperage depends on factors like its size and power consumption. Microwaves can be categorized as follows:

  • Compact microwaves consume 500 to 800 watts, which equates to approximately 5 amps.
  • Midsize microwaves consume 800 to 1200 watts, resulting in an approximate usage of 10 amps.
  • Large microwaves consume 1200 to 1800 watts, with an estimated usage of 15 amps.
  • Industrial microwaves generally consume above 1800 watts, requiring around 20 amps.

The ampere usage varies based on the application and type of microwave you are using. This information can aid in calculating your yearly energy consumption and managing your energy bill expenses.

How To Calculate the Amps of a Microwave Oven?

As is commonly known, the United States typically adheres to a power supply standard of 120 volts. This might lead to confusion when comparing microwaves with the same power rating of 600 to 1200 watts, which seem to consume more amperage than microwaves designed for regions operating on 240 volts. The explanation lies in the fundamental Ohm’s Law, a formula for measuring current, where power is the product of two essential electrical parameters: voltage and current. By applying these basic principles of electrical engineering, we can easily determine the current drawn by a microwave. These formulas involve three key parameters: current, voltage, and power. Current represents the amount of electricity drawn by the appliance, while power is the result of multiplying voltage and current.
The driven formula to calculate the amps of the microwave can be written as follows:

Microwave drawn current in amps = Power rating (watts) / Voltage (volts)

The following example will give you a better idea of how to calculate the amps of a microwave using the above formula, Suppose you have a microwave with a power rating of 1200 watts and an input voltage of 120 Volts, Then it will look like

current of microwave in amps = 1200 / 120 = 10 amps, So this microwave requires 10 amps of current from the power source.

What Size Breaker Do You Need For a Microwave Oven?

Determining the right breaker size for your microwave oven is a crucial task. However, you can easily choose the perfect fit by using a basic electrical formula and grasping a few fundamental terms. First, the breaker size hinges on two key factors: the power rating or consumption and the type of circuit protection used for microwave ovens. Power refers to the amount of electricity or energy needed to operate a microwave oven, measured in watts. Similarly, protective circuitry is the safeguarding circuit or wiring connecting your microwave oven and circuit breaker. This circuit can be dedicated, shared, or common for multiple appliances. Understanding these aspects ensures a smooth selection process for the ideal breaker size for your oven.

A dedicated method for safeguarding a circuit involves using an isolated circuit for a single appliance. This means incorporating one dedicated circuit with separate electrical wiring to protect a lone appliance. Conversely, a shared circuit, or common circuit, relies on one breaker to protect multiple appliances. As per the World Electric Standardization, it is always recommended to install an isolated circuit breaker for microwave ovens. This ensures that your circuit remains free from issues like overloading, breaker tripping, and other fire hazards. However, if your shared circuit has a breaker meeting the total connected equipment requirements and has a rating exceeding 30% of the total load, shared circuits become suitable solutions for affordable household protection of equipment.

The derived formula for the size of the breaker is as follows:

1. Circuit Breaker Size (Measured in Amperes) =

Power rating (For shared circuit -Sum of power rating of all appliances) / Input Voltage (V)

The voltage is the potential difference between the two points. In the United States, 120 volts is the standard voltage supplied by the utility whereas other countries may use a 240-voltage supply system. The breaker size is measured in ampere as it is the maximum amount of current that can be handled by the circuit breaker without tripping. Commonly used ratings of breaker are 15 amps,20 amps, and 30 amps.For instance, if you have a dedicated circuit for a microwave oven that has a power rating of 600 watts and takes an input voltage of 120 volts, then you can put both the parameters in the formula of breaker size as follows

Breaker size (in amperes) = 600 / 120 = 5 amp. It shows that the least requirement of your breaker is 5 amps for the Microwave oven.

However, according to the standard you need to use a larger breaker than the measured size, implying 10 amps will be a recommended solution for protecting your microwave oven.

2. For Shared Circuit

In case you have multiple appliances connected in the shared circuit of the circuit breaker, For instance, consider Three pieces of equipment on the breaker which is the microwave with 800 watts power rating, 600 watts for the refrigerator, and 200 watts for the bread toaster, Also all the equipment design to work on 120 volts of input voltage. Apply all the parameters in the formula as follows:

Breaker size (in amperes) = ( power of all connected equipment- 1000 + 600 + 200 ) / 120 = 1800 / 120 = 15 amps.

The above calculation addresses that your minimum requirement size of the breaker should be 15 amps but as per the standard and to avoid marginal error we always use a breaker of larger capacity than the measured one So implying the 20 amps of the breaker will never disappoint you.

In these, you can seamlessly determine the ideal size of the breaker for your microwave oven whether it is connected on a dedicated circuit or shared circuit.

What are the Factors That Affect the Amp Consumption of a Microwave Oven?

When discussing the energy or amp consumption of a microwave oven, various factors play a role. These include the wattage of the appliance, the type of food being microwaved, the duration of cooking, and the surrounding environment. Here’s an elaboration on the major factors affecting the amp consumption of a microwave:

1. Microwave Size

The size of the microwave is a crucial factor. A larger or commercial microwave requires more energy to fulfill its heating needs, especially for a larger cooking area. Additionally, such microwaves often have a higher initial current, and frequent on-off cycles can significantly impact the microwave’s amp consumption.

2. Type of Food

Every food possesses distinct qualities and characteristics. These factors dictate that the time and heat needed to cook the food will vary based on its type or characteristics. For example, food with higher water content requires less heat for cooking compared to the greater heat needed for cooking dry meat or fish.

3. Cooking Duration

A straightforward concept to grasp is that the longer the cooking time, the more power the microwave consumes. As long as the microwave is active, it consistently uses a significant amount of amps or power to maintain the desired heat.

4. Environmental Factors

For those residing in high-humidity regions, the cooking time for the same food will unfortunately differ compared to those in drier environments. The explanation is straightforward: high humidity results in increased water content in the air, leading to more heat absorption. Consequently, your cooking necessitates a bit more time, and the microwave draws additional amps.

Do Microwaves Consume a Lot of Electricity?

Microwave ovens are commonly known for their energy efficiency. They typically use less energy compared to other high-amp kitchen appliances. Even with regular use, the impact on your electricity bill is minimal, with only a slight increase noticeable.

Let’s illustrate this with a simple example. If you use a 1000-watt microwave for 25 minutes every day, it will consume only 0.25 kWh per day. Over a month, this adds up to around 7.5 kWh. When you calculate the cost based on your electricity rate, it proves to be an affordable amount in comparison to other kitchen devices. Additionally, incorporating other energy-saving practices can further reduce your monthly consumption of the microwave oven, and this aspect is explored in the following section.

How Can Energy Be Saved While Using a Microwave Oven?

There are a few effective ways to use a microwave oven and save energy efficiently. These techniques are outlined below:

1. Use the Proper Size of Container

The appropriate size of the container plays a vital role in heating your food. A smaller container requires less energy and time for cooking, whereas using a larger container than necessary wastes energy.

2. Use Settings Effectively

Microwaves come with power settings designed to operate at lower power levels. This helps avoid overcooking and saves more energy than usual.

3. Preheating Not Required

Many users still believe that microwaves need preheating before placing food. However, the latest microwaves do not require preheating; you can directly place the food in the oven, saving energy.

4. Check the Seal of the Door

Ensure that all doors and seals are tightly closed. Even a small gap can result in a notable amount of heat loss and wasted energy.

5. Use a Cooker

Slow cookers are designed to operate on steam, requiring less energy compared to normal utensils.

6. Try to Use a Forced Fan

A forced fan improves the heating process by 2x. This allows you to cook your food at a lower temperature.

7. Choose an Energy-Efficient or Star-Rated Microwave Oven

Microwave ovens come with different star ratings based on their energy efficiency and energy-saving properties. Ensure that a higher number of stars denotes a more efficient device, allowing for greater energy savings.

Amps Does a Microwave Use – FAQs

1. Does the microwave’s wattage affect the amp usage?

Ans: Yes, indeed, the term “microwave oven wattage” defines the power consumption of the microwave. Therefore, the higher the power consumption, the greater the impact on the amps, requiring more amps to meet the power demand.

2. Can using extension cords affect the amp usage of a microwave?

Ans: Yeah, the power or amp consumption won’t increase gradually, but low-quality and damaged extension cords may draw more current than usual. So, it is recommended to use a high-quality cord and check other circuitry.

3. Can using a microwave simultaneously with other appliances affect its amp usage?

Ans: Yeah, if you are operating on a shared network or have multiple devices on a single circuit, the total amps used can overload the circuit, causing the circuit breaker to trip instantly.

4. Does the voltage of a microwave impact its amp usage?

Ans: The power usage of microwaves is significantly influenced by the input voltage. Microwaves with a higher voltage range use fewer amps than those with a lower voltage range, even though the power remains the same for both.

5. Can voltage fluctuations in the power supply affect a microwave’s amp usage?

Ans: Voltage fluctuations within the allowed range can have a minor impact on your microwave’s performance. However, exceeding the acceptable limit frequently raises amp usage and can cause significant harm to your microwave or other connected devices.


As we conclude our discussion, this guide on microwave ovens has substantially addressed the primary query most frequently asked on the internet: how many amps a basic household microwave uses. In response to these inquiries, we have explored various topics that provide a better understanding of the subject. This includes explaining how to calculate the amp usage of your microwave oven using Ohm’s laws. We have also covered all the formulas, accompanied by a general example so that you can promptly calculate your microwave usage.

Apart from this, the guide delves into protective measures designed to safeguard microwaves against overloading, short circuits, and other faults. The guide effectively outlines which size breaker is the perfect solution for your microwave. Furthermore, it contains all the energy-efficient techniques that can significantly reduce your electricity bill when using a microwave oven.

In summary, we can proclaim that we have thoroughly examined every aspect of microwave ovens, whether it’s understanding their usage, calculating amp usage, or implementing energy-saving techniques.

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