From a design standpoint, the iPhone 8 and haven't changed much from the iPhone 7 and 7 Plus. Yes, they have glass backs to help facilitate wireless charging and cosmetically distinguish them from their predecessors. But their dimensions are within fractions of millimeters of their 7 predecessors.
So, what's that all mean for the cases you might want to use with them? Here's the quick skinny.
Many (but not all) softer, more pliable iPhone 7/7 Plus cases will work with the iPhone 8/8 Plus
The iPhone 8 is 0.2mm thicker than the iPhone 7 and around 0.1mm taller and wider. A standard sheet of copy paper is around 0.05mm thick, so that 0.2mm is about the thickness of four sheets of copy paper stacked together. That may not sound like much, but even tiny changes can impact more rigid cases. However, softer iPhone 7 and 7 Plus cases with some play to them are compatible with the iPhone 8 and 8 Plus.
You can wirelessly charge a phone with a case on, so long as the case isn't too thick
We've been testing the new iPhone 8 and 8 Plus with various cases and wireless charging pads and have found that wireless charging works if the case is less than 3mm thick. (It might still work if the case is a little thicker, but the latest charging pads list 3mm or less as a spec for wireless charging). Plenty of protective cases, such as Speck's Presidio Series, Otterbox's Symmetry Series, Tech 21's Evo Series and others are less than 3mm thick and can be kept on the phone while wireless charging.
Rigid metal or plastic cases iPhone 7/7 Plus cases, including battery cases, will not fit the iPhone 8/8Plus
To reiterate, we didn't have any luck when it came to rigid iPhone 7 and iPhone Plus cases fitting the slightly larger iPhone 8 and iPhone 8 Plus. We tried Mophie's Juice Pack Air for the iPhone 7 Plus with an iPhone 8 Plus and it didn't quite fit. (That battery case includes wireless charging support for older iPhones.) None of Mophie's iPhone 7 series cases are listed as being compatible with the iPhone 8 series.
Don't buy an iPhone 7 case assuming it will fit an iPhone 8
If own an existing iPhone 7/7 Plus case, you can check whether it fits your new iPhone 8/8 Plus. But if you're shopping for new case for your iPhone 8/8 Plus, make sure that it's listed as being compatible. Do not assume that an older case will fit, even it seems pliable.
Cases with an extended slot for credit cards on back may not work with wireless charging pads
It depends on how far the extended slot raises the phone away from the charging pad. Again, you want to keep to the 3mm rule to ensure compatibility for wireless charging.
Virtually all iPhone 6S and 6S Plus cases will not fit the iPhone 8 and 8 Plus
A soft bumper case (no back) for the iPhone 6 or 6 Plus may get around an iPhone 8 or 8 Plus, but the camera changes to the later iPhones are problematic for older cases that have camera holes that don't line up correctly.
If you have an iPhone 7 or older model, you don't have to be left out of the wireless charging game
There are plenty of Qi-compatible cases that that include circuitry that plugs into your phone's Lightning port to add wireless charging capabilities. Of course, you'll need to purchase a wireless charging pad to charge wirelessly. Prices for charging pads range anywhere from around $13 for a generic model to $60 for Mophie's new Wireless Charging Base or Belkin's Boost Up. Apple's upcoming , which also charges the Watch Series 3 and the AirPods when they're in their new , will likely cost even more.