How we test microwaves

How we test microwaves

by Jane Darling

Microwaves need to impress in our tests by doing a great job of heating and defrosting food evenly in order to achieve Best Buy status.

What makes a Best Buy microwave?

We will only recommend microwaves that heat and defrost your food quickly and evenly, leaving no overdone or cool parts. If the microwave oven also has a grill or conventional oven, we'll test these functions, too. Watch the video above to see why a Best Buy microwave oven will make a real, practical difference to you.

All microwaves go through a set of rigorous tests to assess how good they are at the important functions we use microwaves for. Our reviews answer the following important questions:

  • How good is the microwave oven at heating?
  • How good is it at defrosting?
  • What's the microwave's grill like?
  • What's the oven like?
  • Is the microwave oven noisy?
  • Is the microwave easy to use?
  • Should I buy it?

Head to our microwaves reviews to discover which ones come out top of our testing and will guarantee great results. 

Alternatively, read on to find out more about exactly how we do our microwave oven testing.

How good is the microwave oven at heating?

We test microwave oven heating with a specially made substance which has a similar consistency to a lasagne when heated in a microwave. We heat the test food on full power and record how evenly microwaves heat it up, whether all parts reach a safe temperature and whether they dry the food out. We also check how well microwaves maintain their heating power if used for more than 15 minutes continuously. Many microwaves lose power, which means that you'll end up needing to cook your food for longer.

The best microwaves heat food quickly and evenly without drying it out. The worst take far too long to heat food up, don’t get food hot enough and leave it shrivelled.

How good is it at defrosting?

We use slabs of lean, minced beef which have been frozen for 12 hours, and set the microwave oven to defrost according to the manufacturer's instructions. We record the highest and lowest temperatures and check for hot or cold spots in the meat. We also defrost frozen mince using pre-set auto-defrost programs where available. The best microwaves defrost meat evenly, the worst start cooking some parts while leaving other parts still frozen.

What's the microwave's grill like?

We test how well grill elements in grill and combination microwaves work by covering the grill rack with white, crustless bread and then measuring the spread and evenness of the heating. The best grill microwave ovens will evenly spread heat to more than 90% of the bread. The worst hardly brown any of the bread at all.

What's the oven like?

We test how well the convection function on combination microwave ovens works by baking trays of fairy cakes. The best combination microwaves will produce well risen, evenly browned cakes. The worst will burn the cakes, or leave some of them uncooked.

Is the microwave oven noisy?

We record microwave noise when heating on full power and when defrosting. The quietest microwaves make about 47dB of noise in microwave mode, while the noisiest make 62dB. This will sound three times louder – and is loud enough to irritate some people.

Is the microwave easy to use?

We assess how easy it is to set microwaves and to carry out simple tasks such as opening the door and cleaning them. The best microwave ovens are very easy to use and are intuitive to set. For the worst microwaves you’ll need to keep the instruction manual to hand.

If you have difficulty with strength or dexterity in your hands, take a look at our selection of the easiest to use microwaves, which includes advice on that to look out for.

71%the score a microwave needs to earn our Best Buy logo

Should I buy it?

All of the tests described above contribute to an overall test rating for each microwave oven, which we convert to a percentage score.

We know that certain functions of microwaves are more important than others, so we weight our testing to reflect this. You've told us that how well a microwave oven heats food is the most important aspect, so this test accounts for a minimum of 40% of the overall score. 

Solo (microwave-only)

  • 50% microwave heating
  • 30% defrosting
  • 20% ease of use


  • 45% microwave heating
  • 25% defrosting
  • 20% ease of use
  • 10% grill 


  • 40% microwave heating
  • 20% defrosting
  • 20% ease of use
  • 10% convection
  • 10% grill 

All microwaves need to score 71% or more for us to recommend them as a Best Buy. We think that any microwaves that score 40% or less should be avoided, so we highlight them as a Don't Buys.

Browse all our Best Buy microwaves