Is there a faster way to count jigsaw puzzle pieces? 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? 
 A: 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.
A: I don't know of one.  To know the number you should have (it may not be exactly 1000), you can assemble the border.  Many puzzles are cut with a rectangular grid and you can multiply the number of rows by the number of columns.  Unfortunately, I have also seen a number where the grid is perturbed in a small region of the center and the count is changed by 1 or 2.
With an accurate scale, if you have more than one puzzle in the same series, you could weigh the pieces.  The thickness and outer dimensions will be nominally the same.  Whether they are controlled within 0.1%, however, may be questionable.
A: I once tried once piece on a digital scale, then weighing the lot, however I did not find this to be a very accurate way of determining a amount of puzzle pieces.
A: Note: While the thread may have long served it's purpose, I am proposing the following for archival purpose.
You can take a photo after scattering them on a white background and use any software that uses thermal imaging to count, or use infrared beam by having them slide in a narrow strip at an angle that will interfere with the light registering a 'tick'.
A: The only way you can guarantee the jigsaw is complete is to physically do the jigsaw.
Some jigsaws, particularly, Waddingtons & Tower Press jigsaws, have pieces with five connectors so even if you do the border and count the rest, you're not certain it's complete.
For example; some 500 pieced ones may have 502 pieces even the border is 20 x 26 pieces (520), some 750s have 750 pieces even though the border is 24 x 32 (768).
You could also have the other extreme where some pieces are in two bits some 1000 pieced. Some Waddingtons/Tower press ones have this setup with the border 38 x 26 (988).
Any jigsaws with whimsies will also be tricky in relation to 'just doing the border' pieces.
As I've said, earlier, best do the jigsaw, to be certain.
Good luck. :)
A: If you get access to a precision balance you can find the weight of a single piece, then count by finding the weight of all pieces.
There are different types of pieces so of course you’ll have to adjust for that
