Will Wireless Phone Chargers Damage Credit Cards? (ANSWERED)

Wireless phone chargers are a popular choice these days for their convenience. No need to have messy cables lying on your desk, or search around for a power outlet in the dark. Just plonk your phone down on the wireless charging pad and you’re good to go!

But does it hold any risks – specifically to your banking cards should you store them in one of those card-carrying wallet phone cases? This article will get to the bottom of this question once and for all.

How does the magnetic stripe work on a credit/debit card?

The magnetic stripe on the back of your card is made of tiny iron particles under a plastic film. ­These tiny magnets can be magnetised in either a north or south pole direction. Which means static information can be “written” into the stripe. 

When you swipe your card through a card reader, it reads the information. Similar to a tape recorder head.

What are wireless phone chargers? (Electromagnetic field/induction explained)

Wireless phone charger stations use electromagnetic induction. The magnetic field creates electric currents inside a conductor. This is used to power your phone’s battery without plugging directly into a cable. 

These days, most mobile phones such as the Apple iPhone and Samsung Galaxy S models support wireless charging. This is extremely convenient for our ‘get up and go’ lifestyles. 

Is it possible for magnetic fields to damage a magstripe?

Cell phone and wireless charging manufacturers will warn against leaving credit and debit cards with a readable magnetic strip in the wallet area of your phone case when wirelessly charging. 

This is because the magnetic fields generated by the coils in your charger and phone have the potential to alter iron particles in the magstripe on a card that are used to hold data. 

If the magnetic stripe is damaged it will not work when swiped through the card reader.

EMV chips (used to make your card more secure) and RFID chips (enable contactless payments) are not affected by magnets and so are at no risk of being damaged. RFID chips are also found in security badges and key fobs.

Despite the industry warnings, however, our own tests demonstrate that the likelihood of your bank cards becoming unusable due to being exposed to wireless chargers is slim to none!

The below sections have been laid out to explain why these opinions conflict, whilst sharing the safest way for you and your banking cards to continue charging wirelessly. 

Are wireless phone chargers safe to use around credit cards?

Using a wireless charger to charge your smartphone’s battery could in theory damage the magnetic strip on your banking card, credit card, or identification should they be placed between the phone and charger pad. 

This is because the iron-based particles that hold data (such as name, address, account number, etc.) make a credit card readable when swiped and can be permanently altered from their original north or south pole direction when exposed to a magnet – or a strong electromagnetic field.

When it comes to wireless charging, which is based on the basic principle of transferring energies between two coils (sound a bit Nikola Tesla-y? It should!).

The coil within the wireless charging station has to be connected to an outside power source to create an electromagnetic field that contains an alternating current (AC).

When the second coil (like the one found inside your smartphone) enters the electromagnetic field, the circuit is completed and converted into a direct current (DC), thus charging the battery of your phone.

Samsung and Apple (who at the same time are happy to sell the MagSafe wallet designed to fit onto the back of your phone) certainly think this electromagnetic threat is a concern to be heeded. 

As demonstrated by the YouTube Channel Supermagnete, direct contact with a powerful magnet immediately damages even the high-quality magnetic strips on a credit card.

However, we couldn’t find any conclusive evidence of whether exposure to weaker magnetic fields such as those generated by wireless chargers (such as a MagSafe or magnetic Qi chargers) could result in the same damage being sustained. 

The only way to truly test whether wireless chargers damage credit cards was to experiment ourselves. 

One of our credit cards (that lacked an RFID chip) was placed between a Samsung S10+ and a Moshi Otto Q wireless charger, in direct contact with the charger pad. 

No phone case was used to remove any buffering effect that it may have had. The thought is that if the credit cards manage to survive this degree of exposure then they should have no problem when further protected by the barrier of a phone case. 

For reference the power output of this charging setup was 9W, and at the time of writing our plastic credit card had been exposed to 12 hours of active charge time.

After wireless charging overnight, the magstripe and EMV chip were all tested on four consecutive days and found to be working just fine, demonstrating that a 9W wireless charger had no negative effect on our credit card. 

Day	Card Contact Time With An Active Wireless Charger (Hours)	Does The Credit Card Still Work?
1	3	Yes
2	6	Yes
3	9	Yes
4	12	Yes

Wireless charging uses radio waves and so does not emit ionizing radiation and thus presents no risk to your phone or your health.

Round up

The worry associated with wirelessly charging your smartphone while having valuable cards in the wallet plagues many. 

Though our test demonstrated that a 9W wireless charger does not generate enough of a magnetic field, and research of others suggests that your credit cards will be just fine when placed upon a wireless charger, we recommend you take heed of Apple and Samsung’s advice and take them out of your case to stay on the safe side.

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