I want to calculate difference over storage usage. I'm looking for the difference between the number A and the number B. I'm using a simulator A Number = 106581282816 -> Int64 (freeDiskSpaceInBytes) B Number = 250790436864 -> Int64 (totalDiskSpaceInBytes) When I use the calculator, the result is 0.42 as I want. -> A / B When I calculate in Swift, the result is 0 and I couldn't find a solution. How can I solve this? Here is the code I print to the console: print(UIDevice.current.freeDiskSpaceInBytes / UIDevice.current.totalDiskSpaceInBytes) --> Result: 0 I am using the following extension.   // MARK: Get String Value   var totalDiskSpaceInGB: String {     return ByteCountFormatter.string(fromByteCount: totalDiskSpaceInBytes, countStyle: ByteCountFormatter.CountStyle.decimal)   }   var freeDiskSpaceInGB: String {     return ByteCountFormatter.string(fromByteCount: freeDiskSpaceInBytes, countStyle: ByteCountFormatter.CountStyle.decimal)   }   var usedDiskSpaceInGB: String {     return ByteCountFormatter.string(fromByteCount: usedDiskSpaceInBytes, countStyle: ByteCountFormatter.CountStyle.decimal)   }   // MARK: Get raw value   var totalDiskSpaceInBytes: Int64 {     guard let systemAttributes = try? FileManager.default.attributesOfFileSystem(forPath: NSHomeDirectory() as String),        let space = (systemAttributes[FileAttributeKey.systemSize] as? NSNumber)?.int64Value else { return 0 }     return space   }   var freeDiskSpaceInBytes: Int64 {     if #available(iOS 11.0, *) {       if let space = try? URL(fileURLWithPath: NSHomeDirectory() as String).resourceValues(forKeys: [URLResourceKey.volumeAvailableCapacityForImportantUsageKey]).volumeAvailableCapacityForImportantUsage {         return space       } else {         return 0       }     } else {       if let systemAttributes = try? FileManager.default.attributesOfFileSystem(forPath: NSHomeDirectory() as String),         let freeSpace = (systemAttributes[FileAttributeKey.systemFreeSize] as? NSNumber)?.int64Value {         return freeSpace       } else {         return 0       }     }   }   var usedDiskSpaceInBytes: Int64 {     return totalDiskSpaceInBytes - freeDiskSpaceInBytes   } }