Ask Kat: Will Purse Magnets Damage my Credit Cards?


this is a common concern for many of our customers. After all, there’s quite a bit of misinformation circulating about the circumstances under which magnets can scramble the magnetic strip on credit cards, but you know what? I’ve been using magnetic closures in bags for years now and never EVER had a problem with a demagnetized credit card or hotel key, I’ve always figured this to be a misunderstood risk, if not an exaggerated one.

3/4" invisible sew-in magnetic snaps (1 matched set per pkg)
3/4″ invisible sew-in magnetic snaps (1 matched set per pkg)


But here’s the deal… since we’ll be calling for two such magnets in the flap closure for our new design, I thought it might be a good idea to be proactive this time and do a little research ahead of time, so I can offer a more scientific answer to the inevitable questions that will be coming…. and here’s a few things I found out!
1) Not all magnetic stripes are created equal. Did you know this? Because I sure didn’t! Evidently the magnetic stripe on the back of cards comes in two varieties.  Typical credit cards require a VERY  strong magnetic strength to demagnetize them, (typically ~4000 gauss), but because the magnetic stripe on hotel key cards and gift cards can be written over & over, it’s MUCH easier to de-magnetize them (by a magnetic field of 300 gauss or less).

2) It’s easy to tell if your card has a strong or a weak magnetic field. Hotel keys and other cards which can be re-written generally have stripes that are a light brown color, but the stripes on bank credit and ATM cards are very nearly black…In general, the darker the stripe, the stronger the magnetic stripe and the less susceptible it is to being scrambled by another magnetic field.

3) It isn’t the strength of the magnet that’s important, it’s the duration of exposure. Even the mightiest junkyard magnet won’t erase your card’s data if the exposure is brief, but that little refridgerator magnet that can barely hold up that cute little picture of your cat can — if the exposure is long enough. (don’t believe me? Check out the video below created by CreditCards.Com)

4) The key to keeping your cards safe is to keep a bit of distance between the magnet and the magnetic strip on your card. In order for a magnet to scramble a magnetic strip, it’s pretty much going to have to come in direct contact with it. As a matter of fact, the magnetic field emitted by a cell phone can actually demagnetize a credit card if it’s allowed to be in direct contact with the magnetic strip for along enough period of time.

So…. what precautions can we take to keep our various cards safe?

First and foremost- Do not store your cards in such a way that the magnetic stripe is allowed to “get cozy” with another magnetic field. Here’s some practical, everyday ways you can keep all of your cards safe and operating correctly for years.

  1. Always store your cards in separate slots in your wallet or purse to prevent demagnetization or damage to the magnetic stripes. NEVER store your cards “stripe-to-stripe”, which can also cause de-magnetization! ( I never knew this!)
  2. If you don’t have credit card slots in your purse or wallet, look for individual plastic or paper credit card holders to protect each card.
  3. MRI machines are dangerous to credit cards. MRI stands for “magnetic resonance imaging,” and with good reason; these pieces of medical equipment use large magnets to create detailed images of things inside the body. The magnetic fields they create are so strong that you shouldn’t even bring your cards in the same room with one of these instruments.
  4. Be cautious around security tag deactivators. Some stores have small surfaces at checkout stands that a cashier can run a pricey item over to deactivate its security tag. Whether they will demagnetize your card however, is hit or miss. Some of these deactivators use radio waves to decommission the tag; they pose no threat to cards. Others use magnets, and those can cause damage. To be safe, always put your card back in your wallet promptly after paying.
  5. Our sew-in invisible magnets are actually LESS threatening to your cards than the old-style clamp-in magnets are. That’s because our disc magnets are encased within a plastic layer that’s roughly 1/32″ thick. That may not sound like much, but even that much distance can be enough to lower the magnetic field below the strength required to scramble a typical credit card, even if it’s placed in constant contact with the card. (Also, there’s usually going to be at least one other additional layer of fabric or foundation material between the magnet and the card, providing additional protection.)
  6. Never just drop your card into your handbag, allowing it to just tumble around loose. I know it’s tempting to do this when you’re in a hurry, especially with hotel key cards, but remember, it takes a far weaker magnetic field to deactivate your hotel key, so it’s actually MORE important to store them safely than your credit or ATM card.

CCmagnetAnd finally…

Despite claims of demagnetization, scratches and small bends are the #1 reason that cards have to be replaced. . Even the faintest scratches can do enough damage to make your card’s information unreadable. So, if your credit card malfunctions, look for scratches. Magnetic stripes can even be damaged by being stored in a HOT car.

Because anything that causes physical damage to that stripe has the propensity to keep it from being useful in an electronic transaction situation.

But, now it’s YOUR turn!

I really enjoyed researching this piece because I never realized how much I didn’t know about the magnetic stripes on the back of my cards! But how about you? Did you learn something new today? Does this post make you feel better about using magnetic snaps, or are there other questions you still might have?   🙂


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26 Comments So Far, You're Next!

  1. Great information Kathy!!
    I learned some of this years ago the hard way when the magnets on a Travelon purse kept de-magnetizing my condo room key but not my credit cards. The agent at the desk explained this as soft and hard coding of the cards, so I came home and removed the magnets so it wouldn’t be an issue again. I also had my cell phone do the same thing to my room key when they were in the same pocket.

    I’ve never seen this explained so well…… thanks for doing the research and educating us!! 🙂

    • Thanks Jonell- I honestly never knew there was a difference between the strip on hotel keys and on credit cards either and I think there’s a lot of misinformation out there about magnets in purses (no surprise there, right?) so I hope this post helps in that regard. 🙂

  2. Really good information. Thanks for doing the research. I did know about the cell phone and the hotel key cards. I learned that one the hard way when I put my phone and my key in the same pocket for a couple of hours. I won’t go into details, but the trip to the front desk for a working key was highly embarrassing. I’ve been careful about keeping my phone away from my credit cards ever since, just to be on the safe side.

  3. Thanks along with all the other comments. Most of this was new news to me. I am getting ready for a trip and this very timely. Thank you for your research!

  4. Thanks for all this great information that I did not know.


  5. I have forwarded this information to family and friends.
    I bet most didn’t know any of this. Thank you very much.

  6. I didn’t know much of this either, and it’s good information to have. Thanks for researching and sharing. On a similar note, I was told not to use magnets around my sewing machine, but I’ve sewn the purse magnets without adverse effect. Now I’m wondering if I could have kept my magnetized pin holder. I loved that holder and still miss it, but I was afraid to use it near the machine.

    • Gosh I’ve never heard this Beth. Is it the computer programming that would be hurt? I have a feeling that its much the same as the credit cards. Whatever it is that would be hurt, the magnet would have to placed right on it in order to hurt it! There’s no computer inside my machine, so i guess I'[m lucky in this regard. I just think the whole issue has been blown WAY out proportion by the media. The main thing is to keep magnets from actually coming in contact with the cards or phone or whatever. 🙂

      • Yes the machine is computerized. From what you found out about credit cards, I’m thinking that I could have kept the pin holder which just sat by the machine. I think I was afraid that I’d scoot it over to touch the machine by mistake. Definitely, I wouldn’t want to attach a magnet directly on the machine. Maybe I should contact the company that makes the machines. I agree that the media often blows things out of proportion. Social media does that also. It’s sometimes hard to separate facts from fiction.

  7. I have put my cards opposite of each other in the little pockets of my bags.. 1 have the credit card of ID strip up–the next will have it down & so forth–have not had any problems–the reason I have done this for years is I DID unscramble a card years ago–& it was because I had both strips at the same my wallet I only have 3 slots–so I do that with debit card credit card & a store credit card–I really have no need for any other card…my other stuff have no strip–so they go behind in a pocket on both sides of the wallet. It works for me.

  8. Your timing is perfect – I’m getting ready to use a purse magnet and have always felt a little uncomfortable with them. Now I feel much better. Thanks for all the interesting information.

    Cheri S

  9. CharliAnn Olney

    Even so, I still use purse and/or wallet slots only for non-strip cards. I use an RFID proof wallet for all my credit cards, magnetic loyalty cards, or any thing else that can be read with a RFID Reader. Especially when traveling! There is almost always a spare small pocket for the Hotel key card.

  10. Like you, I have never had a problem with a magnetic snap and my cards. I have had hotel keys zapped by my cell phone, however. I had to have one key replaced twice before I realized what was causing the problem.

  11. I have never worried about the magnetic closures, but I did think any direct contact with a magnet would ruin the cards no matter how weak the magnet was. I really appreciate the trouble you took to let us know the facts, Thank you !

  12. My husband had his magnetic clip-on sunglasses in his shirt pocket and put a hotel room key in the same pocket and it was demagnetized.

    • Wow! But that proves the point exactly! It’s all about duration of DIRECT contact. Thanks for sharing

  13. Great information. Thanks – I appreciate all the information you send out – it really helps to know what’s going on in our busy world today, and you help a great deal by debunking myths and putting out the “true scoop” on all sorts of things. Thanks, and have a great week!
    Barbara L.

  14. I’m probably repeating others, but here’s my two cents. I enjoy free patterns because I get to see if I like the way a designer drafts their patterns and instructions. If I don’t, no harm, no foul. I’m not out anything but time. However, if I like their style, I feel more confident buying their (usually) more intricate patterns. So yes, I like being able to access free patterns, but I also like being able to honor the artist by purchasing their more complex offerings.

  15. delaine leclair

    i have been all over google to get the answer to my question. hopefully you can help or maybe someone could help. i have ordered a cell phone case for my galaxy, it is a wallet case with 2 card slots. i am currently at a hotel and have a cpl credit cards and debit cards along with my key card. i am wondering, will my cell phone or the magnetic closure on the wallet case harm my cards?

    • It’s hard to say without seeing it. So sorry. It will depend on where the magnet is in relation to the cards and cell phones them selves can be a bit hazardous to cards.

  16. Just bought a cell case with card slots that has a magnetic closure & didn’t think about the risk to credit cards until searching & stumbling on your blog. Thanks for the info!

  17. Is there something I could do to cover a round purse holder (magnet) so it doesn’t demagnetize my credit cards while it’s in my purse? Thank you!

    • I’d like to help you Christine but I need a good deal more information. I also think the best forum for answering this question (since it might take a bit of back and forth) is not this blog, but rather, by email.
      So… feel free to email me but I need to know where the magnet is located. is it in your wallet?, it is laying loose in your purse? is it sewed on your bag flap etc???? and where are your credit cards in relation to the magnet. Thanks

  18. Brilliant, thankyou! I was looking because I put those exact magnets in a wallet for my husband, so thank you!!!!

  19. I used to be the lady at a credit union that people came to when they had problems with credit or debit cards. I can vouch for the negative affects of prolonged exposure to even low magnetic fields. One lady had her card demagnetized by her eel skin wallet! Which was, of coarse, in direct contact with the strip constantly. I can’t remember a single complaint resulting from the usual magnetic purse closure. Scratches were the usual culprits.

  20. Thank you so much for this information. I shared it on Facebook for my many friends who are unaware.