How Long Will the Heating Oil in my Tank Last?

Posted on October 31 2018

One question you do not want to be asking yourself on a cold, blustery, New England night: how much heating oil is left in my tank – and how long will it last? To find the answer, the first thing you need to know is: what size heating oil tank do you have?

Understanding Heating Oil Tank Sizes

Most heating oil tanks have a total volume of 275 gallons, but they can safely hold 240 gallons of heating oil. Please note there are a few different types and sizes of heating oil tanks out there, and they can range from 120 to 330 gallons.  So, if you really want to be sure of the tank size, you can get out the old tape measure and physically measure the dimensions of the tank.  Click here to get the dimensions of home heating oil tanks.  

After you know your tank size, next you’ll need to figure out how much heating oil you have in your tank. Check the oil tank gauge - most likely on the top of your tank – but not always; it usually looks something like this:


If your gauge is at a half, you probably have about 120 gallons in your oil tank. (Remember - a typical 275-gallon residential oil tank safely holds 240 gallons of heating oil). If you don’t have a gauge or it’s broken (I’m talking to my friend Glenn here!), we recommend you spend a few dollars and call your local HVAC company to get a gauge installed - it’s worth the expense to ensure you don’t run out of oil.

Understanding How Much Heating Oil is in Your Tank

Based on your oil tank gauge reading, our handy little grid below gives you an idea of the approximate number of gallons of heating oil you have left in your oil tank – and how many gallons you’ll need to fill it back up; feel free to print this out and leave it by your heating oil tank.

Oil Level Gallons you have Gallons you need to fill your tank 
Empty  (oops!) 00 240
1/8 30 210
1/4 60 180
3/8 90 150
1/2 120 120
5/8 150 90
3/4 180 60
7/8 210 30
Full 240 00

*Figures above are approximate and based on a 275-gallon tank.

How Long Will the Heating Oil in my Tank Last?

Now, back to our original question – how long will the heating oil in my tank last? As a general rule of thumb, for a 2000 square foot home, a ¼ of a tank of heating oil will last approximately a week during the winter.  However, there are a lot of factors that can affect your usage:

  • The outdoor temperature - colder outside temps increase the rate of heating oil consumption. Winter = more fuel use, summer = less fuel use.

  • How warm do you keep your house - setting higher temperatures increases the rate at which heating oil will be consumed.

  • What are you heating? – you know you’re using oil to heat your home, but is it also heating your hot water? Some homes rely on the furnace to continuously heat the hot water, while others use tankless or electric systems, which reduce oil consumption.

  • Outdoor wind conditions - wind can significantly increase the rate of heat loss from a home, depending on insulation and draftiness.

  • Oil burner efficiency - the efficiency of your heating equipment can vary widely by design, from say 65% efficient for an old, antiquated, not-well-maintained oil burner, to better than 90% efficiency for a newer, high efficiency heating system that is properly tuned.  Just cleaning and maintaining the heating system annually makes a huge difference in how quickly oil is used.

“Order at a quarter”

We always recommend you “order at a quarter.” Mostly because it rhymes and it’s fun to say, but also because it helps prevent running out of oil. And nobody wants to run out of oil. Not only does it typically result in lots of arguing about who forgot to place the order – but it’s also bad for your oil tank. When older systems get below 1/8 of a tank it can cause sediment from the bottom of the tank to get into the fuel lines and gunk everything up. Plus, it’s always a good idea to place an order before you’re right about to run out. It’s like bread and milk at the grocery store - as soon as a storm rolls in people run to the store and buy bread like it’s going out of style. Same thing happens with heating oil – when it gets cold, everyone orders, and with a first come first serve system, you want to make sure your order is in the queue before the mad rush.

Interested in more heating oil tips? Check out Heating Oil Use Tips.

Have more questions – we have answers. Be sure to check out our Heatable FAQs for more very punny answers to all your burning (ha – get it?) heating oil questions.

Learn more about Heating Oil

Visit our Ultimate Consumer’s Guide to Heating Oil for everything you need to know about heating your home with #2 heating oil.

Stay cozy out there!

The Heatable Team