by now meaning

[love-you-mom]

She must be home by now.

Does it mean :
1- She must be home before now.
or
2- She must be home now.

 

[SoothingDave]

Context?

If someone is conjecturing, it would mean that the person would surely have arrived home by the time the person spoke the sentence.

"By" is a deadline. It means on or before. If I say "be home by midnight" I don't care if you come home at 10. As long as it is not after midnight.