"book by" or "book until"

[ibrisa7]

Does "book by 4 February" mean that I can book on 4 February?

Or does it have to be "book until 4 February"?

Thanks

[Tdol]

I would interpret it as meaning that the 4th of February is the last day when you can book.

[emsr2d2]

I would interpret it as meaning that the 4th of February is the last day when you can book.

So would I although if I had no way of checking, I would make sure I booked by February 3rd at the latest, just in case.

[SoothingDave]

The other way would be "book before" not "book until."