It is very difficult to know how much glue is needed to glue together a jigsaw puzzle. Everything depends on how many layers you want to apply and what you intend to do with the jigsaw.
One thing we can say is that if you apply a thin layer of glue (generally a sufficient amount to keep the pieces together), one bottle of our Clementoni Puzzle Glue should be enough for 4 x 1,000-piece jigsaw puzzles.