REASONS TO BUY
Good at defrosting meat
Great cost-to-value
Popcorn function works well
REASONS TO AVOID
Not the most convenient to use
Heating performance could be better
Panasonic NN-SB458S Review
This product pairs reasonable testing results with an affordable price, standing out from the competition with great cost-to-value
This product delivered an overall above-average performance.
Credit: Laura Casner
By David Wise ⋅ Senior Review Editor ⋅ July 7, 2025
Contributions From: Austin Palmer
RELATED: The Best Microwaves of 2025
Our Verdict
Earning mostly favorable results across the board in our microwave testing, we wouldn't actively dissuade anyone from purchasing the Panasonic NN-SB458S. It scored average or above average across our four performance metrics, and we don't think it's overly expensive in the world of kitchen appliances. This isn't our favorite microwave we tested, with multiple other products considerably outperforming it, but it gets the job done.
Our Analysis and Test Results
The NN-SB458S is a sleek and modern-looking offering from Panasonic that gave satisfactory performance across our range of tests. It's smaller than many of the microwaves we tested, having a 10.6" turntable and measuring only .9 cu. ft., but is still big enough to accommodate most plates and foods.
An affordable option for heating your frozen dishes.
Credit: Laura Casner
Heating
Excelling most at leftover heating, the Panasonic scored well across our range of heating tests, aside from pizza heating.
The Panasonic struggled with the pizza heating test. One slice of pizza was hardly heated at all, and the other had some hot spots, but the heating seemed patchy and uneven across the slice.
We found that one side was just a tiny bit cooler than the rest during our Panasonic NN-SB458S heat test.
Credit: Laura Casner
We noted a warmer section in the center of the test disc and a larger, close-to-burnt ring around the perimeter that turned dark brown but not quite black. The middle and outsides seemed to heat up much faster than the area in between, but nothing was burned.
The Panasonic has some quick button features, but far less than the others we tested.
Credit: Laura Casner
Starting with a temperature of 59 degrees, we heated a cup of water for 45 seconds, and the end temperature was 148, netting an increase of 89 degrees.
We tested every facet of these microwaves.
Credit: Matt Lighthart
Our soup was heated to just about the perfect temperature to eat right away, but it would quickly become cold if not eaten right away. The temperature of the soup measured at 153 degrees after being heated.
We did dock some points for these two slices coming out with some significant thermal differences.
Credit: Laura Casner
Frozen Foods
In our testing of the NN-SB458S, the frozen burrito was heated to an ideal average temperature of 181 degrees and had very little variation in the temperatures taken throughout.
The lasagna test didn't fare as well. A few spots met or exceeded the ideal temperature of 165 degrees, but there were quite a few cold sections, and the largest swing was a whopping 52 degrees lower than the high of 180 degrees. The hot pocket heated well, with only a 7-degree difference between temperatures on average. The pot pie heat test scored well as well, showing only a 6-degree temperature difference on average, and in all places the probe measured, the temperature was above the minimum of 165 degrees.
Defrosting
In our test, the NN-SB458S selected ten minutes and twenty seconds to defrost the frozen ground meat and instructed us to flip it halfway through the time allotted. None of the ground meat was cooked while defrosting, and very little of the meat was still somewhat frozen. We felt that it defrosted well enough that it would be ready to cook in the state that it finished.
The Panasonic's popcorn function works great, tying some of best appliances we tested.
Credit: Laura Casner
Presets
The NN-SB458S lacks quick start buttons that require just one touch to get things heating, and the lighting is less than optimal. The timer is simple enough and easy to use, but when measuring how much friction the microwave has when placed on different surfaces, it moved every time we touched it. Whether pushing buttons to start heating or opening and closing the door, this microwave could benefit from some rubber feat to hold it in place during use. The popcorn setting works very well, leaving behind only 9 unpopped kernels and no burning on any popped pieces.
The Panasonic NN-SB458S doesn't have quite as many convenience features as some of the others.
Credit: Laura Casner
Should You Buy the Panasonic NN-SB458S?
If you're looking for a microwave on a budget that is a solid performer across a wide range of tasks, the NN-SB458S may be right for you. However, if your microwave use often involves heating up pizza, this isn't the right microwave for you. Aside from the pizza heating, this microwave is an adequate performer at a fair price. The only caveat is some lack of ease-of-use features, which some other models perform better.
We tested the best microwaves on the market to determine how well they perform.
Credit: Matt Lighthart
What Other Microwaves Should You Consider?
If, after reading this review, you think this may not be the right microwave for you, check out some of our other top performers identified during our testing. The Magic Chef MC110MB is a top pick that stood out in our testing, especially when heating frozen foods.
Side-by-Side Comparison
Compare Panasonic NN-SB458S versus top competing products:
—David Wise and Austin Palmer
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