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Is Your Toaster Oven Lying About Its Temperature?

Never burn dinner again! Discover how accurate your toaster oven’s temperature is with an inexpensive oven thermometer and a few simple tests.

Oven thermometer inside a large countertop oven.

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The dial says 350 but your charred food, it’s telling a different story.

Disappointed, you think “I followed the directions, what did I do wrong?”

Maybe nothing. Maybe your toaster oven is lying.

Dun Dun Duuuun!

Okay, it’s probably more of a miscommunication.

See, if your toaster oven isn’t calibrated correctly when you say 350° it might think you’re actually asking for 325°, 375° or even 400°!

While you can’t re-calibrate most toaster ovens you can make sure you’re both speaking the same language.

With the help of an oven thermometer and a few tests, you can find out if the temperature inside your toaster oven matches the temperature you’re asking for.

Oven thermometer and small wooden spoon of sugar on a piece of foil.

But First, Let’s Clear Some Space

So, about those clearance requirements for the space behind and above your toaster oven, yeah they’re not just for safety reasons.

When not in use, we store our new toaster oven pushed up against the kitchen wall. During our first round of tests, I forgot to pull it forward.

Every result was at least 25 degrees higher than the screen temperature.

Funny thing is, our toaster oven has been crazy reliable. I couldn’t figure out what was going on.

Then it hit me, Doh!

Large countertop oven on a kitchen counter.

After moving the toaster oven forward and away from the wall the temperature was accurate again.

Maybe your running-hotter-than-expected toaster oven might need some extra breathing room?

If that’s not the case, grab an oven thermometer and get started.

Do You Preheat Your Toaster Oven?

Closeup of control panel on a large toaster oven.

With the exceptions of broiling cheese, melting chocolate, reheating leftovers or making toast we preheat our toaster oven.

If you preheat, how do you know when it’s ready?

Many toaster ovens have a feature where they beep when they’re done preheating and have reached the desired temperature.

Don’t Believe The Beep

Your toaster oven may be telling the truth but for the sake of your double chocolate chip cookies, it’s best to Trust But Verify.

How To Test Your Toaster Oven’s Preheating Feature:

  • Start with a cold toaster oven
  • Adjust your toaster oven’s baking rack to the middle position.
  • Place an oven thermometer in the middle of the rack
  • Set the toaster oven to Bake and the temperature to 350°F.

Large countertop oven with an oven thermometer inside.

When the toaster oven signals it has finished preheating* check the thermometer to see if the temperature is accurate.

*If your toaster oven does not have a preheat feature check after 4 or 5 minutes.

Someone’s A Fibber

Our toaster oven signaled that it was done preheating after 3 minutes ↓

Closeup of oven thermometer on a cooking rack.

But it actually took 6 full minutes for it to reach 350°F. #pantsonfire

Not a huge deal but now we know to ignore the pavlovian beep and give the toaster oven a few more minutes to preheat before we start baking.

Why Starting Temperatures Matter

Say you’re baking muffins, a loaf of bread or batch of peanut butter cup cookies

This Food52 article does a great job of explaining how that initial burst of warm heat and a consistent-ish temperature affects your baked good’s ability to rise and the end texture.

Does it Stay That Temperature The Whole Time?

To maintain a steady temperature, toaster ovens cycle their heating elements on and off or dim them high and low. (For more temperature talk check out this toaster oven review video from America’s Test Kitchen – skip to minute 4:21)

Using the method below (adapted from a Cnet article) you can test if your toaster oven’s cycling is consistent and accurate.

  1. Continuing from the test above, keep your toaster oven turned on at 350 degrees and your thermometer inside.
  2. Set the cook time for at least 60 minutes.
  3. Record the initial temperature.
  4. Over the hour, check and record the temperature every 15 minutes.
  5. At the end, add all of the readings together and then divide by the number of readings taken to get an average temperature.
  6. If your toaster oven is heating/cycling accurately the average should be close to your original temperature.

Our toaster oven averaged a temperature of 356°F. Not a huge difference in temperature but we should probably shorten our cook times by a few minutes.

What About Convection?

Remember how in our 7 Things You Should Know About Convection Toaster Ovens article we talked about reducing the cooking time and temperature?

Cookies on a baking sheet inside a toaster oven.

Guess what? You can use the tests above to find out exactly how much to reduce the temperature for your specific toaster oven!

How We Tested Our Toaster Oven’s Convection Function:

  • Starting with a cold toaster oven, we set it to 350 degrees and Bake with the convection feature on.
  • At the 3 minute mark, the preheat beep fibbed again.
  • After 10 minutes the thermometer had reached 375 degrees (25 degrees more than the 350 the screen showed).
  • We checked it three times over the course of an hour and each time the thermometer was at exactly 375 degrees.

Thermometer on a cooking rack inside a toaster oven.

Two Things We Learned

  1. Our toaster oven is the most evenly and consistently heated when the convection function is used.
  2. When using the convection function the temperature will always be 25 degrees higher. So if we want 350 we better ask for 325 or shorten the cook time.

Other Ways You Can Test Your Toaster Oven’s Temperature

There’s a test involving boiling water and one that uses a candy thermometer too.

We tried this sugar testing method (because it looked like fun) from Food.com. The original poster adapted it from the book Cooking With Geeks.

The basic idea is that sugar melts at 366.8F / 186C (though that seems up for debate these days).

Supplies Needed: 2 squares of foil* and 4 teaspoons of white sugar

 Toaster Oven Tip

*Most manufacturers have specific instructions for the use of foil in their toaster ovens. Make sure to consult your manual before using foil in your toaster oven.

More toaster oven tips: 4 Surprising Things I’ll Never Use In Our Toaster Oven

Pile of white sugar on a piece of foil.

To Test If Your Toaster Oven Runs Hot:

  • Preheat your toaster oven to 350°F
  • Place 2 teaspoons of sugar in the center of a foil square
  • Place foil on the center rack in your toaster oven for 15 minutes
  • If your toaster oven is accurately calibrated the sugar should brown but not melt

Piles of browned sugar and white sugar on pieces of foil.

Our sugar was golden brown but starting to melt. This seems consistent with our slightly higher average cycling temperature from the test before.

Also, the heating elements in a toaster oven are way closer to the sugar than a standard oven so that may have played a part in the melting too.

To Test If Your Toaster Oven Runs Cold:

  • Preheat your toaster oven to 375°F
  • Place 2 teaspoons of sugar in the center of a foil square
  • Place foil on the center rack in your toaster oven for 15 minutes
  • If your toaster oven is accurately calibrated the sugar should melt

Oven thermometer and foil with sugar on a cooking rack inside a toaster oven.

Our sugar was completely melted and turning a deep caramel color.

If you have the choice, we’d stick with the thermometer to get hard numbers you can use. But if you’re just trying to get a sense of how off or accurate your toaster oven is the sugar test is helpful and an hour of sciency fun.

Overhead view of burnt, browned, and white sugar on pieces of foil.

We know it’s frustrating when your toaster oven is delivering burnt bagels instead of the lightly toasted results you expected.

But before you give up on your little oven try some of the tests above.

With a few adjustments to your temperature requests that garage sale toaster oven you got for $10.00 could be exactly what you need for baking up the tiny treats you love!

6 Comments

  1. I have an old black and decker space saver under the counter. It was fine until last year. I tested every single temperature and in order to cook correctly I have to set the dial 125 degrees cooler. So if I am to cook at 475, I have to set the dial to 350. It sucks. It all started with the door sticking. We fixed that and since then, the temp is off. I can not find any toaster oven with the same inside dimentions and same outside dimensions. the bigger inside ones are way too big, take up too much space, on the counter. NONE of them are under the counter, either. The black and decker under counter is much smaller inside than the old one I have. I made a chart with all the temps on there: if I want this, set it to that.

    1. That’s a bummer, Tanya. Those under-the-cabinet toaster ovens are almost unicorns, we had one in my house growing up and I loved it too.

      You might want to check out the new Ninja Foodi Convection Oven. It’s rather large but you can flip it up against the wall when you’re not using it and get some counter space back.

  2. Have you ever left the oven thermometer in the toaster oven while food is also cooking? Or only while empty? I recently bought a new Black and Decker convection toaster oven. In this model, convection is always on – there is no option to bake without. I put the oven thermometer in to test it without any food. I set the dial to bake at 350 and the thermometer consistently read 375 for an hour. When I put any type of food in, the temp drops to 325 and stays there. Any thoughts?

    1. Hi, Joanna!

      I’ve left the thermometer in our traditional oven before but don’t think I’ve done that in our toaster ovens yet. I’ll have to try it and see if we get similar results to what you’re experiencing.

      Like a regular oven, the temperature will drop in your toaster oven when you open the door and add your food but it should recover and come back up to the dial temperature eventually.

      Out of curiosity, is your food turning out okay and taking the right amount of time to cook? If it is, I’d wouldn’t be too concerned with the thermometer’s temperature. If it’s not cooking as expected then I’d talk to the manufacturer.

      Most toaster ovens use a consistent heat to quickly reach the preheated temperature. After that, the elements are alternated on and off to keep the temperature even.

      This is just a guess but if your food is cooking properly, it may be possible the elements are heating (cycling on and off) in a way that’s difficult for your oven thermometer to measure accurately.

  3. i actually bought a oven thermometer to test the temperature in my toaster oven. it is actually 50 degrees off on the temperature it says. really upsets me because i use my toaster oven instead of my real oven. my last toaster oven was accurate on temperature, but it was a General Electric and was the best. i bought a Black & Decker TO3250XSB. don’t waste your money on this toaster oven if you want the degrees to be off by 50 degrees. i called about this to Black & Decker and they told me that an oven thermometer will be inaccurate in a toaster oven to verify the temperature, they would not do nothing about it being that much off. any people with same problem, please help !!!!!

    1. Hi Cathy, you didn’t mention if the temperature was 50 degrees lower or higher than it should have been? If it was lower, then you know you’ll want to increase the temp on the dial 25 to 50 degrees to get it where you want for your recipe. If it was higher, then you can dial back the requested temp.

      Hope that helps 🙂

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