How Much Gas Does a Generator Use

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Are you wondering “How much gas does a generator use?” Just how much gas will you need for the power you want? How long will your generator run before it runs out of gas? Well my friend, look no farther. I will try to answer this question for you.

What Type of Generator do you have?

To find the answer to “How much gas does a generator use?” You need to determine what type of generator you have.

5000 watt Standard Generator

A 5000 watt standard generator will consume on average about .75 gallons of gas per hour. That is 18 gallons of gas per day. This is not very efficient if you ask me. A standard generator is a mobile generator that is basically an engine with an electric output. They only produce DC current. Standard Generators are able to make more power than inverter generators, but they are less fuel efficient.

Standard Generator Example

For example the A-iPower AP5000V 5000-Watt Gas Powered Portable Generator has a 4 gallon gas tank that provides up to 12 hours of run-time at 50% load. Scroll down to learn more about load.

Inverter Generators

Inverter generators are more efficient than standard generators. Aside from having a motor, inverter generators have a battery, alternator and inverter. Inverter generators produce AC and DC current. Inverter generators have more fuel efficiency and smaller gas tanks.

Inverter Generator Example

For example the A-iPower SUA2000iV Ultra-Quiet 2000-Watt Portable Inverter Generator uses about 1 gallon every 6-7 hours. It has a 1.1-Gal. Fuel tank. It provides up to 7 hours of run time at 50% load, 4 hours of run time at 100% load.

Types of Fuel Used

To complicate matters more, different generators use different types of fuel. According to, the following chart shows the amount of fuel used by fuel type.

Fuel TypeKilowattsFuel Used Per Hour
Gasoline5-kw generator.75 gallons
Diesel8-kw generator.5 gallons
Propane6-kw generator1.42 gallons
Natural Gas7-kw generator118 cubic feet

Gas Emissions

It is important to know that gas generators emit greenhouse gasses into the environment. When purchasing a generator it is good to check that the generator is EPA compliant. Inverter generators are more expensive, but they produce less pollution compared to standard generators. Inverter generators are more likely to be EPA compliant than your standard gas guzzling generator. If you are very concerned about pollution, you should check out solar generators, which use no gas at all.


How much gas your generator uses also depends on how much load you are putting on the generator, or how much energy you are drawing from it at once. The more electronics, lights, and appliances you have running, the more load you are putting on your generator. The more load you put on your generator, the more gas you will use. That is why it is important to have energy efficient appliances and devices before hand.

For example, the DuroStar DS4000S Gas Powered Portable Generator has a fuel tank capacity of about 4 gallons. According to the generator specs, it has a run time of 8 hours on 1/2 load capacity. The generator has a rating of 4000 peak watts and 3,300 running watts.

To figure out what your load is, add up the watts of all of the appliances you will be using. Here is an easy cheat sheet from

AC central3500
Coffee maker (2 cups)600
Electric Range (medium size) 1800
Refrigerator (large)780
Living Room Lights60
Television (new technology) 80
Gas Washer850
Gas Dryer3400
Garage Door1000

If your load is greater than 1/2 of the peak rated load, you will consume gas faster. So at full capacity, in this example, the generator’s tank might last 4 hours instead of 8 hours. At 75% load capacity, the gas tank will likely last around 6 hours.

Check the Specs

Check the specs on the generator you want to purchase (or already have) to see if it mentions the run-time. The run-time will be for 1 full tank of gas. The tank sizes vary, so keep that in mind and notate what size tank your generator has. This will help you figure out the answer to the question “how much gas does a generator use?”

How Much Gas Does a Generator Use – Conclusion

So I hope I helped you figure out about how much gas a generator uses. There are many factors to consider. It is best to check the specifications of the generator to find out the exact rate of gas usage. Then you can figure out if your load will burn the gas at the average rate of usage.

Utility Hacker

The utility hacker is passionate about saving people money on their utility bills and protecting the environment. I was a utility bill auditor in Texas for 10 years. I am sharing my knowledge to help people survive the crazy utility industry that we live in today.