calcs.homes
calcs.homes
Enter your bean bag's diameter to estimate how much filler you need to refill it or top it off.
Estimate only — assumes a roughly spherical bag shape; actual fill varies by bag style.
We treat the fully filled bag as a sphere and compute its volume as (4/3) × π × (diameter ÷ 2)³, convert cubic inches to cubic feet by dividing by 1,728, then multiply by your fill percentage to get the actual amount of filler needed. The result also divides into standard 0.5 cu ft filler bags (or 15 L bags in metric) so you know roughly how many bags to buy.
Bean bags are intentionally under-filled to 60-70% of their full geometric volume, because a sphere packed solid with beads or foam sits stiff and doesn't contour to your body — leaving room for the fill to move is what makes the chair comfortable. Treating the bag as a perfect sphere is a simplification, since real bean bags flatten under weight, but it's close enough for a shopping estimate, and rounding bag count up is cheap insurance against having to top off later.
An overfilled bean bag becomes stiff and doesn't conform to your body — leaving room for the fill to move is what makes a bean bag comfortable.
Measure straight across the widest point of the bag when it's fully filled and sitting on the floor — most manufacturers also list this in the product size chart.