[Math] faster way to count jigsaw puzzle pieces

puzzle

I have a number of old 1000-piece jigsaw puzzles I'd like to sell. I'd like to make sure they are complete first. Is there a faster way to determine whether there are exactly 1000 jigsaw pieces than physically picking up and counting every single one of them?

Best Answer

The answer is in the title of this website - Stack. Measure the thickness of one piece, then stack them up and measure the height, place them in a tube, preferably clear, of small enough diameter so the pieces won't fall down the side. A graduated cylinder would be perfect.