Why is microwaving at full power for half the time, not the same as microwaving at half-power for twice the time. What's happening that's beneficial when the pulse is off half the time?

2 Answers 2


A microwave heats pretty unevenly — most of the heating goes into the outmost portion of the food, and even that isn't always even (e.g., bottom probably gets fairly little). That's not unique to a microwave; a pan mainly heats the bottom; an oven...

Mostly, the lower power settings give more time for the heat to even out by inside the food. Depending on the food, you could run at a higher power setting and keep pulling it out to stir, rotate, etc. Often quicker, but much more work.


far from an expert, but my guess it´s because the food continues cooking while the microwave is off...it is similar to leaving a dish unopened for a while after cooking...

if I had to guestimate, I would use 75% continuous cooking time to approximate a 50% intermittent time

  • 3
    Not to mention that terms like "half power" "75%" power and whatnot are nothing more than conventions. You can't actually reduce the power of a microwave. Instead if you set your microwave to 50%, what the microwave does is simply turn the microwave "antenna" off for half the time. Commented May 14, 2019 at 23:27
  • @SteveChambers True for some microwaves, but not all. Microwaves with inverter technology actually cook at the assigned power setting for the set time without pulsing/turning on and off. It's not a brand new thing. We've had ours for ~17 - 18 years.
    – Cindy
    Commented Jan 8, 2020 at 12:15

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