How Long Will A Generator Run On 5 Gallons Of Gas?

Are you wondering how long a generator will run on 5 gallons of gas? It is an important question to ask especially if you’re looking to buy one.

Owning a generator is essential, especially when you suffer frequent power outages. A generator ensures your home runs as normal without any power issues. However, the biggest issue for most people is the generator’s fuel consumption.

So, how long will a generator run on 5 gallons of gas?

This can vary depending on the generator load. However, most generators can run approximately for 8 hours on 5 gallons of gas. Different generators will offer different run times. Some can run even longer while others run for less time.

However, it’s never a good idea to have a generator running continuously for hours. Generators are designed to operate for short periods with regular maintenance in-between. For example, you need to frequently add fuel, grease and service them.

Dive in as we discuss gas consumption in generators, runtime and how to reduce fuel consumption.

What Affects Generator Gas Consumption Rates?

As noted earlier, fuel consumption is a big factor when buying a generator. Do you want to be refilling the generator tank after every two hours? So, what are the factors that affect gas consumption in generators?

What Affects Generator Gas Consumption Rates

Below are some factors that affect gas consumption rates.

1. Generator type

The type of generator you buy goes a long way in determining the consumption rates. While most generators are built similarly, they consume fuel differently.

When choosing a generator, consider a model that suits your consumption needs. The ideal generator model should match your load and consumption. Here are common generator types:


A standby generator is designed for emergencies when there are sudden power outages. This type of generator is crucial if you live near inclement weather areas.

A standby generator for a sump pump packs a lot of power and can consume more fuel. They are designed to power all your loads when there is a sudden power outage.

Their large size means they consume more fuel than most generator types.


This is the smallest generator on the market and one designed to power electronics. Furthermore, the units support pre-charging using electricity. They don’t require gas to run.


Portable generators are quite popular and make a great option for persons that spend more time outdoors. They are what you commonly use when camping in the woods.

Portable generators come in varying sizes to meet different user needs. You can choose a small or large size depending on your load. Some models feature larger tanks, while others feature small tanks.

If you’re looking for a generator to power your home, consider a standby generator. Portable generators are only ideal for a few items. The generators are ideal for powering laptops and small home appliances.


Lastly, you can consider the tri-fuel generators, which allow the use of up to three fuel options. The generators work with gas, liquid propane, and gasoline, making them versatile.

Apart from tri-fuel generators, you can also find dual-fuel generators.

2. Fuel Type

Next, you need to consider the fuel type running on your generator. The type of fuel you choose plays a huge impact on the consumption rate.

Fuel Type

Some fuels burn faster than others. When choosing a generator, consider the type of fuel it runs on. Here are a few fuel examples.


Diesel is the most efficient when you want the generator to run for longer. Fuel burns slower and takes longer to burn. However, the biggest issue with diesel fuel is the emissions to the environment.

If you’re conscious about the environment, you might consider other options. Diesel emits dirty and toxic elements into the air.

However, its impressive consumption rate makes it a great choice.

Here is a table showing diesel consumption in generators.

Generator size in kWh Fuel Consumption in Gallons/Hour
1000 71.1
1500 106.5
2000 141.9
2250 159.6

The table shows the impressive consumption rate of diesel per hour. Apart from polluting the environment, you’ll be saving a lot in terms of fuel consumption.

Natural gas

If you have gas lines coming to your home, you might consider natural gas. While it’s not the most eco-friendly, it is cleaner than diesel.

Natural gas burns at incredible rates and will cost you more. It is only considered when you have natural gas lines at your home.

Here is a table showing natural gas consumption in generators

Generator size in kWh Full Load Consumption in cu.ft/hour
1000 9883
1750 17264
2250 22184

You can see the huge fuel consumption difference between diesel and natural gas.


We also have gasoline which is one of the most readily available fuels. In fact, most generators run on gasoline. Gasoline is a popular choice with moderate consumption.

How much gas do generators consume per hour? On average, a 5-gallon gasoline generator will consume 0.75 gallons per hour. Furthermore, gasoline generators are quite affordable. However, they do require frequent fueling if you use them regularly.


Propane is another excellent fuel source that compares to gasoline. It is quite easy to source and a popular choice for standby generators.

Propane is a great choice, especially in rural areas. It is also economical for running standby generators.

Most generator models burn up to 3 gallons per hour on average. This means 500 gallons of propane can power most generators for a week.

3. Load

Lastly, you need to consider your load. Load simply refers to the number of appliances that run on the generator power. If you’re using the generator to run the entire house load, the fuel consumption will be higher.

Generator Load

However, if you’re using the generator for a few electronics, the consumption will be lower. Consider your load size when deciding on a suitable generator size.

Most generator manufacturers advertise their generators based on a 50% load. This means the generators can power more load than what is indicated.

How Long Will A Generator Run On 5 Gallons Of Gas

How long a generator runs on 5 gallons of gas depends on various factors. The fuel type, generator model, and load hugely determine how long a generator runs on 5 gallons.

How Long Will A Generator Run On 5 Gallons Of Gas

As indicated above, most average 5kWh generators consume 0.75  gallons of gas per hour. Larger 30kh generators can consume up to 3 gallons per hour.

Make sure you understand your load, generator model, and fuel when calculating fuel consumption. You can expect a 5-gallon generator consuming 0.75 gallons per hour to run for 7-8 hours.

How To Reduce The Fuel Consumption For Gas

You can reduce fuel consumption in generators in several ways. We all want our generators to run for longer using less fuel. Below, I’ll discuss a few tips to help you save gas consumption on generators.

Regular servicing

How often do you service your generator? Regular maintenance can reduce fuel consumption. Have a tendency to have a professional service your generator regularly.

If there are damaged components and parts, replace them with genuine ones.  Avoid counterfeiting spare parts as these can lead to more damage.

Minimize usage

As I mentioned earlier, generators are not designed for continuous use. Use a generator only when necessary. Unless you’re using the generator for commercial purposes, daily usage is not recommended.

Using a generator frequently leads to more fuel consumption. Have other energy sources and use the generator when absolutely necessary.

Remove carbon deposits

Diesel generators, when burning, produce ash carbon polymers. The polymers accumulate on various generator parts like the valve, piston, and injector.

Accumulation of black deposits makes the generator release black smoke and increase fuel consumption. Clean the generator regularly using a cleaning detergent. In addition, make sure you change the oil after each cleaning.

Avoid overloading and underloading

As we mentioned, generators are rated for 50% of the load. Make sure you don’t overload the generator as this will increase fuel consumption. It also makes the generator work harder, leading to a shorter lifespan.

It is recommended you measure your energy needs and buy a matching generator. You don’t want to overwork a generator beyond its limits.

Under loading, the generator also means the engine takes longer before hitting the maximum operating temperature. This can lead to excess fuel consumption. When a generator struggles to work, it tends to consume more fuel.

Maintain the ideal coolant temperature

The generator’s engine needs cooling using a coolant. For most generators, water is used as a coolant. When the engine overheats, it leads to complete combustion causing excess fuel consumption. Make sure you maintain the correct water temperature.

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