Print the size (megabytes) of Data in Swift

Use yourData.count and divide by 1024 * 1024. Using Alexanders excellent suggestion:

    func stackOverflowAnswer() {
      if let data = UIImagePNGRepresentation(#imageLiteral(resourceName: "VanGogh.jpg")) as Data? {
      print("There were \(data.count) bytes")
      let bcf = ByteCountFormatter()
      bcf.allowedUnits = [.useMB] // optional: restricts the units to MB only
      bcf.countStyle = .file
      let string = bcf.string(fromByteCount: Int64(data.count))
      print("formatted result: \(string)")
      }
    }

With the following results:

There were 28865563 bytes
formatted result: 28.9 MB