Storage is more precious than ever, with rising drive prices driven by AI datacenter demand. That makes the familiar gap between advertised capacity and usable space harder to ignore. Engadget reports that a 512GB drive recently showed only 477GB available in Windows. The explanation is usually math, not deception: drive makers often use decimal units, while Windows uses binary units. A 1TB drive can therefore appear as 931GB, even though nothing is lost.
The same discrepancy does not exist on the Mac, where decimal units are used, and neither Microsoft nor Apple appears ready to change its approach. The operating system itself is another major consumer of storage. Engadget notes that iOS 27 occupies more than 22GB on a 128GB iPhone 16 Pro, and Windows 11 can take over 81GB on a gaming laptop. Add cache and swap space, and the usable capacity shrinks further.
The practical takeaway, according to the article, is to be conservative when shopping and using storage. Overestimate how much space you need, and don't panic when the displayed capacity falls short of the label. A few dozen gigabytes of overhead is an acceptable trade-off for a working device.