How Long Will A Portable Generator Run on A Gallon of Gas

  • By: Umer.A
  • Date: November 18, 2021
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A portable generator can run for around 8 to 10 hours on one gallon of gas.

Portable generators come with a grab-and-go power facility, which offers an ideal situation for everyone dealing with power shortages. These are not huge enough to give power to a whole house.

However, smart power management can keep the essentials work well for a long time. For camping and outdoor activities, these portable generators come in handy. However, the run time of generators depends on the size of the tank.

Alongside this, the gas consumption criterion of the particular generator also affects its performance significantly. However, if you fill it up with around one gallon, it will likely run efficiently for around eight hours.

How To Determine A Generator’s Fuel Consumption?

Determining a generator’s fuel consumption is possible and not that difficult for sure. However, it requires an entire process to go by, and eventually, you will be able to determine its fuel consumption.

To start, you will have to fill the fuel tank. Now the amount of fuel you fill the generator up with depends upon your budget. So, no matter how much power you use, take the exact notes.

You need to set up the generator and use the load setting according to your regular usage. The next steps would be to run the generator for one hour and fill the fuel tank again.

Notes need to be taken regarding the exact amount of fuel you need to add to the tank again. For example, if you need to add one gallon to top it off, your generator’s fuel consumption is one gallon per hour.

To improve your generator’s fuel consumption, you need to take care of a few things. First, professional cleaning of the generator every six months will enhance its fuel consumption and efficiency.

Though you can do that yourself at home, getting professional help will make things better for you in the long run. In addition, the removal of the carbon deposits further reduces the generator’s fuel consumption.

Overloading the generator produces more power, but it affects the efficiency adversely. In addition, as the generator has to work harder than usual, it consumes more fuel.

Hence, it is necessary to let the generator work according to the power generation for the limit it has been made for. Going ahead of this power limitation will leave excessive carbon deposits and reduce efficiency.

Lastly, reducing its usage and working only during extreme needs will enhance its fuel consumption.

What Type of Generators Is More Efficient on Gas?

When it comes to buying a generator, the options available to the buyer tend to confuse him.

While producing electricity, the conventional portable generators tend to keep the speed uniform throughout their work. Therefore, it helps in saving fuel to a greater level than its alternatives.

Contrary to that, the inverter generator has to put in extra effort to produce more electricity, and the fuel used by it in this process also increases manifold. At the same time, with more production of energy, the noise generated by it also augments.

Which Fuel Types Are More Efficient?

Considering the fuel economy, it can easily be said that choosing gasoline over propane will bring in better results. This is because propane comes with a lesser energy ratio than gasoline, with its one gallon having lesser energy by 27% than one gallon of gas.

Therefore, the octane rating of propane is much higher than gasoline. This higher rating comes as an advantage for many engines, optimizing their working through this type of gas.

However, in terms of cost-efficiency, propane generators are way expensive than gasoline ones. But, at the same time, this gas is relatively cheaper in contrast with gasoline.

Does The Output Power Affect Fuel Efficiency?

Fuel efficiency talks about the amount of fuel that a generator would consume by working for a particular amount of time and generating the output power.

Each generator sold by the manufacturer comes with a pre-set power generation, and it can’t generate more power than that.

Therefore, with the lesser output power of the generator, the fuel efficiency is more. This is vice versa, and the more power a generator produces, the more fuel it requires to burn.

Hence, it is always recommended to buy a generator that is strictly in accordance with the power it is necessary to generate. Putting extra load on it will deficiently affect and eventually ruin its fuel efficiency.

Can You Refuel a Running Generator?

No, refueling a running generator is highly risky and poses great danger. A generator that is already working is quite hot. And it may cause ignition the moment a drop of fuel spills on it. This eventually may lead to a huge fire explosion causing significant damages.

Therefore, it is always recommended not to refill the generator while running, even while being outside. A single mistake can cause damage to you and the people around you.

How Long Will a Generac Generator Run On 5 Gallons of Gas?

Typically, it depends on the size and power generation capacity of the generator. However, on average, a generic generator can run for around seven to ten hours on 5 gallons of gas. This is calculated because it comes with a fuel consumption rate of 0.75 gallons per hour.

How Long Will a Generator Run On A 20lb Tank of Propane?

A generator that runs on around 500 gallons would work for about a week before burning out completely. A generator that comes with a 20lb tank can run for 4-5 hours.

How Do You Remove Gas from A Generator?

Removal of gas from a generator requires you to take some extra care. Each step in the process has to be followed precisely to reduce the chances of any mishap.

The first step in removing gas from a generator is to open the gas tank cap properly. Next, you need to turn off the fuel valve and move the cover away. Ensuring to set off the fuel valve is necessary to avoid any spillover of the fuel. Now remove the aluminum clip, put the fuel tube into the container and remove all the gas.

Next, locate the screw at the incubator’s base, open it and let the gas go out. Let it drain till the time every particle has come out.

How Much Gas Does A Generator Use?

Different generators consume different amounts of gasses, which depend on two things: their size and power generation. This relation is relative. So, as the size of the generator increases, the gas used by it also increases.

Alongside, if the power output of the generator is high, the gas used by it is also more than the regular one. It also depends on the type of gas that the generator uses. For instance, gasoline burns off faster than propane.


Proper cleaning and emptying of the gas from the generator are necessary, as they will add to its efficiency manifold. The running of the gasoline generator depends on the power it generates and its size.

Nonetheless, as a general consideration, as portable generators are to be taken around, they are mostly small in size and do not require much gas to work properly.