Bean Bag Filling Calculator (litres of beads for round, square, ball & pear shapes)

Understanding the bean bag filling calculator — concept and principle

This calculator estimates how many litres of filling beads you need for a bean bag or pouf, based on its shape, size and how full you want it. It also tells you how many bags of filling to buy.

Cylinder × fill share: with the default inputs the result is 267 L (3 bags of 100 L).

How it is calculated

Cylinder (round pouf): V = π × d² × h ÷ 4

Box (square pouf): V = length × width × height

Ball: V = π × d³ ÷ 6

Pear (truncated cone): V = π × h × (D² + D × d + d²) ÷ 12

Litres = m³ × 1,000; filling = volume × fill level %; ft³ = litres ÷ 28.317

Bags = filling ÷ bag size, rounded up

The principle

The inner cover is treated as a simple geometric solid whose volume can be calculated from its dimensions. Bean bags are rarely filled to the top, because some room lets the beads move and shape around your body. Polystyrene (EPS) beads settle and compress over the first months, so many people top up later.

Worked example

Default inputs: round pouf, diameter 90 cm, height 60 cm, fill 70%, 100 L bags.

Cover volume = π × 0.9² × 0.6 ÷ 4 = 0.382 m³ = 382 L.
Filling = 382 × 0.70 = 267 L = 267.2 ÷ 28.317 = 9.44 ft³.
Bags = 267 ÷ 100 = 2.67 → 3.

Each point is the calculator re-run with only “Diameter, or length for a box (cm)” changed; the gold point is the default example. Change the inputs above and this chart follows your numbers.

Diameter, or length for a box (cm)	Filling needed (L)
22.5	17
45	67
67.5	150
90	267
112	417
135	601
180	1,069

How to read the result

A firmer pouf needs a higher fill level; a lounging bean bag often works best at 60–75%. Expect to add 10–20% more beads after several months as they compress.

Common mistakes

Measuring the outer cover instead of the inner liner.
Filling to 100%, which makes the bag hard and uncomfortable.
Spilling beads; fill outdoors or in a bath, as they cling with static.

Keep in mind: Keep loose beads away from small children and pets; they can be inhaled or swallowed. Use a cover with a child-safe zip.

Frequently asked questions

How many litres for a large bean bag?

Often 250–400 L, depending on size and fill level.

Can I use other fillings?

Yes, such as shredded foam or recycled fibre, but volume and feel differ.

Why does my bean bag go flat?

EPS beads compress with use; topping up restores the shape.

Sources: Standard geometry volumes of cylinder, box, sphere and frustum; 1 ft³ = 28.316846592 L exactly (NIST Special Publication 811)

Checked 9 Nov 2026. Volumes of a cylinder, box, sphere and frustum of a cone (standard geometry); 1 ft³ = 28.316846592 L (exact). Fill level and bag size are example values.

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