Bean Bag Filling Calculator — EPS Beads & Foam Volume
Buying the right amount of bean bag filling is tricky — too little and the bag sags, too much and it's rock-hard. Enter the bag diameter and your preferred fill level to find out exactly how many litres of EPS beads or shredded foam to buy, plus the approximate weight.
Bean bag shape
cm
%
Filling type
Loose volume of EPS beads or foam required
524 L
volume- 1
Radius (m)
100 ÷ 2 ÷ 100 = 0.5Diameter in cm divided by 2, then converted to metres for the volume formula. - 2
Internal volume (L)
(4 ÷ 3) × π × 0.5³ × 1000 = 523.6 - 3
Filling needed
523.6 × 70 ÷ 100 = 367
How does this calculator work?
Filling needed (litres) = (4/3)πr³ × 1000 × (fill% / 100) for a spherical bag, where r is in metres. A 100 cm bean bag at 70% fill needs ~370 L of EPS beads (~7.4 kg). Buy 10–15% extra to allow for settling. EPS bulk density ≈ 20 kg/m³; shredded foam ≈ 25 kg/m³.
Formula
How this is calculated
A round bean bag chair is modelled as a sphere; a flat-bottomed variant as a hemisphere (half-sphere); and an oval or teardrop shape as approximately 80% of the equivalent sphere. The internal volume in litres drives everything: it tells you the total space inside the outer fabric cover.
The fill level (70–80% is the sweet spot for most people) determines how much of that volume is occupied by the filling material. EPS (expanded polystyrene) beads are the most common filling — they are very light, with a bulk density of around 20 kg/m³ (0.020 kg per litre). Shredded memory foam is slightly denser (~25 kg/m³) but holds its shape better over time.
The weight result uses these approximate bulk densities and is an estimate — actual product densities vary by brand and grade. Filling is typically sold by loose volume (litres) so the primary output is litres. Note: bean bag filling compresses over time; buying 10–15% extra on top of the calculated amount is recommended so you can top up the bag as the beads settle.
Frequently asked questions
A typical round adult bean bag with a 100 cm diameter has a volume of about 524 litres. At a 70% fill level you need roughly 370 litres of EPS beads — around 7–8 kg. Larger XL bags (130 cm diameter) can need 600–700 litres of filling.
70–80% fill is recommended for comfortable everyday use — the bag moulds to your body and rebounds. Below 60% it feels deflated and flat; above 90% it becomes stiff and loses the characteristic "sink in" feel.
Yes — EPS beads gradually compress and break down over 1–3 years of regular use, so the bag slowly flattens. Top up with 10–20% of the original volume every 12–18 months to maintain comfort, or switch to shredded memory foam which is more durable.
TG we-Calculate Editorial Team. (2026). Bean Bag Filling Calculator — EPS Beads & Foam Volume [Online calculator]. TG we-Calculate. https://we-calculate.com/calculator/bean-bag-filling-calculator
TG we-Calculate Editorial Team. "Bean Bag Filling Calculator — EPS Beads & Foam Volume." TG we-Calculate. 2026. https://we-calculate.com/calculator/bean-bag-filling-calculator.
TG we-Calculate Editorial Team, "Bean Bag Filling Calculator — EPS Beads & Foam Volume," TG we-Calculate, 2026. [Online]. Available: https://we-calculate.com/calculator/bean-bag-filling-calculator
@misc{wecalculate_bean_bag_filling_calculator, title = {Bean Bag Filling Calculator — EPS Beads & Foam Volume}, author = {{TG we-Calculate Editorial Team}}, howpublished = {\url{https://we-calculate.com/calculator/bean-bag-filling-calculator}}, year = {2026}, note = {TG we-Calculate} }
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