Is It Safe to Buy a Used Microwave? Check the Door First

Yes, a used microwave is usually safe to buy, as long as the door is in good shape. The U.S. Food and Drug Administration says plainly that microwave energy will not leak from an oven in good condition, and that you should not use one whose door does not close firmly or is bent, warped or otherwise damaged. So the age of the oven matters far less than the state of four parts: the door, the hinges, the latch and the seals.

With a used microwave, you are not buying a box. You are buying a door. Check it first.

Below is what the federal rules actually require, what decades of real testing found, and a two-minute check you can do on any secondhand or open-box microwave before you pay.

Are older microwaves safe to use?

Most are. Since 1971, the FDA has required every microwave sold in the United States to meet a federal performance standard (the rule is 21 CFR 1030.10). According to the FDA's microwave safety page, that standard does three things that matter to a used buyer:

1. It sets a leakage limit for the oven's whole life, not just the day it leaves the factory: 5 milliwatts per square centimeter, measured about 2 inches from the surface. The FDA adds that energy falls off quickly with distance; at 20 inches it is about one hundredth of the reading at 2 inches.
2. It requires two separate door locks, called interlocks, that stop the oven "the moment the latch is released or the door is opened."
3. It requires a monitoring system that shuts the oven down if one or both of those interlocks fail.

That is why an old microwave that has been treated well is generally not the danger people fear. The weak point is not the years. It is physical damage.

What did real-world testing of old microwaves find?

The best public evidence comes from a university that tested its own ovens for decades. The University of Delaware's Environmental Health & Safety office began checking campus microwaves in 1987 and has tested several hundred of them for leakage and for whether the door interlocks work.

What it found is reassuring and useful at the same time:

• Leakage turned up only in rare cases.
• Where it did, the level was well below what is considered able to cause harm.
• Every oven that leaked was physically damaged in an obvious way: a damaged door seal, damaged hinges or latch, or damaged interior walls.

That last point is the whole lesson for a secondhand shopper. The problems that matter are the ones you can see. If you look closely at the door before you buy, you are checking the exact parts that failed in real ovens.

What should I check on a used microwave before buying?

Do this in person, with the oven unplugged for the look-over and plugged in only for the last step.

The last row is the one the FDA is firmest about. If a microwave keeps operating with the door open, the agency says to stop using it immediately. On a used oven, that is not a repair project; it is a pass.

A simple way to run that test: put a cup of water inside, start the oven on a short time, then open the door. Everything (light, fan, turntable, hum) should stop at once. Do not run the oven empty to test it; the FDA notes that some models should not be operated with nothing inside, so a cup of water is the safer way.

Every oven sold in the U.S. must also carry a label saying it meets the federal safety standard, so a missing label is a fair reason to ask more questions.

How do I check if a used microwave was recalled?

Write down the model number and look it up on the Consumer Product Safety Commission's recall site, cpsc.gov, before you pay. This step matters more for used goods than new ones, because some recalls outlive the companies behind them.

A real example: in 2007, the CPSC announced a recall of about 300 Sunbeam over-the-range microwaves installed in mobile homes, because internal electrical arcing could cause a fire. No injuries were reported, but the firm had gone out of business, so there was no repair or refund on offer. The CPSC's advice was to stop using the microwave, discard or destroy it, and not donate or resell it. A small recall like that is easy to miss, and the model number is your only way to know.

We have a step-by-step guide to doing this for any product: how to check if a product is recalled before you buy used. If you are also looking at countertop cookers, see our note on checking an air fryer or pressure cooker's model number.

Is radiation the biggest risk with a used microwave?

No. The FDA says most microwave injuries are burns from hot containers, overheated food or exploding liquids, not radiation. The NIH's Division of the Fire Marshal adds a sobering figure in its 2016 safety bulletin: more than half of microwave burn victims are under 5 years old. That is worth knowing if the oven is going into a family kitchen, and worth thinking about when you choose where to place it.

A few habits from the FDA and the NIH fire marshal make any microwave, old or new, safer:

• Superheated water can erupt when you move the cup. Adding instant coffee or sugar before heating greatly reduces that risk, the FDA says, and you should not go past the heating times in the manual.
• No metal or foil, and be careful with recycled paper towels and waxed paper, which the NIH notes may contain tiny metal flecks that can spark.
• Stay nearby for popcorn; the NIH warns some ovens can scorch it in as little as two minutes.
• If something catches fire inside, the U.S. Fire Administration's advice is to turn the oven off, unplug it, and keep the door closed until the fire is out. Call the fire department if you are not sure it is.
• Clean it gently with water and mild detergent. The FDA advises against scouring pads and steel wool.

Does a used microwave make sense in a DC, Maryland or Virginia home?

Often, yes, especially for a basement apartment, a dorm, an office break room or a first place where you need something that works today. A countertop model is the easiest used buy: you can see every side of it and test it on the spot. An over-the-range model is a bigger commitment, since it is installed above the stove, so take extra care to get its model number and check it for recalls before it goes on the wall.

If you are shopping for kitchen gear, you can browse what is listed now in the shop or by category, and see items you can buy at a set price on Buy Now. For questions about pickup, payment and how things work at DealsDMV, our FAQ has the details.

The bottom line

A used microwave is a safe buy when its door closes firmly, its hinges, latch and seals are undamaged, its cord is sound, and it stops the instant you open the door. Federal rules have required two door interlocks and a lifetime leakage limit since 1971, and the University of Delaware's testing found that the rare ovens that leaked were visibly damaged. Check the door, look up the model number, and skip anything that fails either test.

Know someone hunting for a cheap microwave for a dorm or first apartment? Send them this two-minute check before they buy.