About

Incorrect fill quantity is the most common reason bean bags lose shape within weeks. Underfilling causes postural collapse and accelerated foam degradation. Overfilling wastes material and makes the bag rigid. This calculator computes the internal volume of your bean bag from its geometric dimensions, applies your target fill ratio (typically 70% - 85% for optimal sink), and converts the result to bead weight using the bulk density of your chosen fill material. Standard virgin EPS beads have a bulk density around 15 - 25 kg/m³. Recycled or shredded memory foam can reach 40 - 60 kg/m³. The tool accounts for these differences to prevent costly ordering errors.

Results assume the shell is non-stretchy. For stretch fabrics (spandex blends), add 10 - 15% to the computed volume. The pear shape uses a composite ellipsoid-cone approximation. Actual volumes may deviate by ±5% depending on seam geometry and fabric stiffness. Always buy slightly more than calculated - compressed beads in shipping bags expand 15 - 20% once unpacked, but settle back within days.

Formulas

The calculator selects the geometric formula based on your chosen bean bag shape, computes total internal volume, then scales by fill percentage and converts to weight via bead bulk density.

Sphere: V = 43 π r³

Cylinder: V = π r² h

Rectangular: V = l × w × h

Pear (ellipsoid approx.): V ≈ π6 W² ⋅ H ⋅ 0.7

Torus: V = 2π² R r²

Once total volume V is determined:

V_fill = V × Fill%100

W_beads = V_fill × ρ

Cost = W_beads × P

Where r = radius, h = height, l = length, w = width, W = widest diameter, H = total height, R = torus center-to-tube-center radius, ρ = bulk density of fill material in kg/m³, and P = price per kg.

Reference Data

Fill Material	Bulk Density	Comfort Feel	Durability	Typical Cost	Notes
Virgin EPS Beads (Standard)	15 - 20 kg/m³	Light, crunchy	1 - 2 years	$3 - 5/kg	Most common; compresses over time
Virgin EPS Beads (Premium)	20 - 25 kg/m³	Firm, supportive	2 - 3 years	$5 - 8/kg	Larger bead diameter; slower flatten
Recycled EPS Beads	12 - 18 kg/m³	Soft, uneven	6 - 12 months	$2 - 4/kg	Eco-friendly; irregular shapes
EPP Beads	20 - 30 kg/m³	Resilient, quiet	3 - 5 years	$8 - 12/kg	Memory-like recovery; premium option
Shredded Memory Foam	40 - 60 kg/m³	Plush, heavy	3 - 5 years	$6 - 10/kg	No crunch; retains heat
Microbeads (0.5-1mm)	25 - 35 kg/m³	Silky, fluid	1 - 2 years	$10 - 15/kg	Used in neck pillows; leaks through zippers
Buckwheat Hulls	85 - 110 kg/m³	Firm, natural	2 - 4 years	$4 - 7/kg	Heavy; best for small meditation cushions
Polyester Fiberfill	10 - 15 kg/m³	Fluffy, pillow-like	6 - 12 months	$3 - 6/kg	Clumps quickly; not ideal alone
EPS + Foam Hybrid	25 - 40 kg/m³	Balanced, supportive	2 - 4 years	$5 - 9/kg	70/30 bead-to-foam ratio common
Natural Kapok Fiber	12 - 18 kg/m³	Silky, lightweight	1 - 3 years	$8 - 14/kg	Hypoallergenic; flattens if compressed
Dried Lavender Blend	60 - 80 kg/m³	Aromatic, firm	6 - 12 months	$15 - 25/kg	Niche; for small sachets or pillow inserts
Shredded Latex Foam	35 - 50 kg/m³	Bouncy, supportive	4 - 7 years	$10 - 18/kg	Most durable; heavy total weight

Frequently Asked Questions

Upright bean bag chairs perform best at 75 - 85% fill to maintain back support. Loungers and floor cushions work well at 65 - 75% for a deeper sink. Gaming bean bags often need 80 - 90% for structural rigidity.

Larger beads (diameter 3 - 5 mm) have more air gaps, resulting in lower bulk density around 15 kg/m³. Smaller beads (1 - 2 mm) pack tighter at 22 - 25 kg/m³. The calculator uses average density per material type. For precise ordering, request the bulk density from your supplier.

The pear shape uses an ellipsoid approximation scaled by a factor of 0.7 to account for the tapered top. Real pear-shaped bean bags vary significantly based on seam placement, fabric stretch, and whether the top is gathered or sewn flat. Expect ±5 - 10% deviation. For critical orders, measure by filling with packing peanuts and emptying into a known container.

Yes. Standard EPS beads lose 20 - 30% of volume within 6 - 12 months under regular use. Order 15 - 25% extra for a refill reserve. EPP beads and shredded latex foam resist compression better and may not need surplus stock.

One cubic foot equals 28.3168 liters. Many US suppliers list fill in cubic feet while European suppliers use liters. The calculator outputs both units. A typical adult bean bag requires 200 - 400 liters (7 - 14 ft³).

Mixing is common. A popular blend is 70% EPS beads with 30% shredded memory foam. To calculate, run the tool twice with each material's density at its respective volume fraction, then sum the weights. The blended bulk density is the weighted average: ρ_mix = 0.7 × ρ_EPS + 0.3 × ρ_foam.