Will Magnets Damage My Phone, Credit Cards or Laptop?
Everyday magnets won’t damage a modern phone, laptop, SSD or chip card. Strong neodymium magnets can erase the magnetic stripe on hotel key cards and some credit cards, confuse a phone’s compass while they’re close, put a laptop to sleep, and magnetize mechanical watches. Keep strong magnets a few inches from these items, and at least 6 inches from pacemakers and other implants (12 inches for magnets 1 Inch and larger).
Item by Item
| Item | What a strong magnet can do |
|---|---|
| Smartphones | Temporary The compass and camera focus can misbehave while a magnet is right against the phone. Move it away; recalibrate the compass if it stays off. |
| Chip and tap-to-pay cards | Chip Safe The chip and antenna don’t store data magnetically, but a stripe on the same card can still be erased. |
| Magnetic stripe cards | Can Be Erased Hotel keys and gift cards erase easily; bank card stripes take a strong magnet up close. Don’t carry magnets in the same pocket or wallet. |
| Laptops and tablets | Temporary A magnet near the lid sensor can put the screen to sleep. Move the magnet; no harm done. |
| SSDs, USB drives, memory cards | Safe They store data electrically. |
| Hard drives | Unlikely Hard to erase with a hand magnet, but don’t stick strong magnets to the case. |
| Mechanical watches | Can Be Magnetized A magnetized watch runs fast. A watch shop can demagnetize it in minutes. |
| Compasses | Can Be Ruined A strong magnet can weaken or reverse the needle for good. |
| Old CRT TVs and monitors | Color Blotches Modern flat screens aren’t affected. |
| Pacemakers and ICDs | Keep Away Read magnets and medical implants. |
Why Card Stripes Erase
A magnetic stripe stores data as tiny magnetized regions. How hard they are to rewrite is called coercivity. Low-coercivity stripes (about 300 oersteds), common on hotel keys and gift cards, are easy to erase. High-coercivity stripes (2,750 to 4,000 oersteds), used on most bank cards, resist much more. In air, 1 gauss of field equals about 1 oersted, so here’s how our magnets compare:
Phones and MagSafe
Phones are full of small magnets: in the speakers, the vibration motor, the camera’s focus and stabilization system and, on most iPhones since the iPhone 12, the MagSafe ring. A magnet won’t wipe a phone’s storage. It can make the compass point the wrong way and may briefly upset camera focus while it’s held against the camera. Both recover once the magnet is removed.
Building a phone mount, case or wallet? Our MagSafe Ring Assemblies are made for exactly that; see the MagSafe installation guide.
Laptops
Most laptops and tablets detect when the lid or cover closes with a small magnetic sensor. A magnet near the palm rest or bezel can trigger it and put the screen to sleep. Moving the magnet away fixes it immediately.
A Simple Distance Rule
For small magnets (up to about 1/2 Inch), a couple of inches is plenty for everyday electronics (implants need more; see above). For magnets 1 Inch and larger, keep about 6 in from cards, watches and compasses. Steel blocks fields too: a Pot Magnet’s steel cup keeps its back side almost field-free.
Sources
- Magnetic Stripe Card Coercivity (Allegion)
- Field values calculated by totalElement from magnet dimensions and N52 material properties.