Can Magnets Damage Your Credit Cards?

Author: , on March 29, 2010

There is speculation about the type of damage various magnets can do to your credit cards. Here are some answers to questions concerning magnets, credit cards and more.

Have you ever heard that magnets and cell phones can react to that magnetic strip on your credit card and make it nothing more than a small piece of plastic that is only useful for getting into locked doors? That may not be so far from the truth. Here are some things you should know about magnets and your credit cards.

Magnetic fields can destroy credit cards. According to Diandra Leslie-Pelecky, a physics professor at the University of Texas in Dallas, any magnetic field can damage your credit card’s magnetic strip. The larger the magnet’s force, the more data it can erase.

Cell phones can delete your credit card information.
Although cell phones have relatively low magnetic fields, they are capable of deleting some or all of the information on your credit card depending on how long the two objects have been in contact with each other.

Leave your credit cards outside if you are having an MRI.
An MRI machine has a huge magnetic field and it can render your credit cards utterly useless if you have them in the room while having an MRI. Bring a trusted friend or relative with you when you have the test so you can leave your credit cards far away from the magnetic fields.

Magnetic closures on purses can be bad news for your credit cards.
Even a magnetic field as small as the closures on your purse can delete your credit card information. Leslie-Pelecky recalls an instance in which she carried her hotel card key in her purse which had a magnetic closure. The small magnet got too close to the card key and made it useless.

Your credit cards could demagnetize each other.
Although Leslie-Pelecky says this can happen, it is highly unlikely. It is most likely that this could happen if your cards are together with the stripes facing each other. However, it would probably take a long time for the cards to become demagnetized as a result.

Scratches on the magnetic strip of the credit card can be a problem. Many people just assume that when their credit card stops working correctly, it is because it has become demagnetized. However, there are other possibilities, such as the fact that a scratch could make the card unusable. Always consider other possibilities before jumping to the conclusion that it became demagnetized.

Credit cards can be a great convenience, but you also have to be careful about how you keep them when you are not using them. Putting them in your wallet is ideal if you do not have any other magnetic forces in the same pocket or purse. Also, be sure to use purses and wallets with non-magnetic closures to avoid the risk of ruining your credit cards. It will save you a lot of headache and hassle in the long run.


  • Goldsword

    July 03, 2012

    Why the hell do they put magnetic closures in wallets and purses anyway? The people do make such products must to totally and utterly dumb! Incidently you can demagnetise those magnetic closures on wallets and purses by soaking the whole purse or wallet in boiling water for 20 minutes. Then letting it cool. It might ruin the wallet though if it is made of leather but it worth a try.

  • JZ

    May 13, 2012

    Magnets erase Hotel Key Cards! almost everytime. i dont know how, because i dont know how the information is stored on the card, but ive seen it happen and tried it myself! so you my friend...are incorrect

  • SMC

    February 21, 2011

    You are a moron. Cell phones magnetic fields are not strong enough to damage or erase you credit cards or hotel room cards. I don't know where you did your homework, but you got it all wrong. Your own cell phone contains a memory card that a very strong magnet could destroy, but you think the weak signal from your cell phone could erase your cards? Preposterous. The reason your card fails could be for many reasons, such as low quality cards re-encoded again and again by a hotel chain, when the cards are not created for that purpose, being scratched by keys or other items in your pocket, or defective door readers/card encoders. I get so tired of people passing myths about as fact, as though they are experts on encoded technologies. Give it a rest, and stop confusing people with your nonsense.

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