Candy Jar Calculator

Guessing-game jars are rarely perfect spheres of identical cylinders — this calculator divides effective jar volume (cubic inches) by the volume of one candy piece, scaled by a packing fraction between 0 and 1 to account for air gaps between irregular shapes.

Random mixed candy packs use an average piece volume — measure one representative piece with calipers or water displacement for better accuracy. Spherical gumballs pack tighter than twisted wrappers.

Example: a 500 cu in jar at 60% packing with 0.5 cu in per piece yields about 600 pieces, with a displayed band near 540–660 for contest answer ranges.

Fill the jar the same way guests will see it — shaking settles pieces and raises the count versus a loose drop-in. Leave headspace below the lid if contest rules forbid overflow. For fundraisers, use a single candy type so variance is lower; mixed minis need conservative packing fractions (about 0.55–0.65).

Spherical gumballs pack tighter than twisted wrappers or irregular chocolate minis. Measure one representative piece with calipers or water displacement rather than guessing average volume from the bag label.

Contest hosts often seal the jar after filling so no one can recount by weight on a scale — photograph the fill method and packing fraction you assumed if you need to defend the answer later. For classroom jars, avoid choking-hazard sizes for young grades.

If you only know cup capacity, convert to cubic inches first — 1 US cup ≈ 14.44 cu in — then enter that as jar volume. Display a contest answer band (about ±10%) so winners can guess near the estimate without requiring an exact hit.

Limits: pure geometry — does not model sticky clusters or soft candy deformation under weight. Not affiliated with any contest or brand.