1kg box = 250 pieces per box
250 pieces makes 48-50 bomboniere with 5 pieces in each
If you need to do 180 bomboniere you would do the following to work out how many kilos you need exactly.
180 (bomboniere) x 5 (pieces of confetti) = 900 (pieces total)
900 / 250 (the amount in each box) = 3.6 boxes
Round this off to the next whole number, which is 4.
You now know you will need 4 boxes to complete your bomboniere.