Helium Tank Calculator — How Many Balloons Per Tank (2026)

A standard 8.9 ft³ disposable helium tank fills about 30 nine-inch or 15 eleven-inch latex balloons. A 14.9 ft³ jumbo disposable fills about 50 nine-inch or 25 eleven-inch. The math is tank cubic feet × 0.85 ÷ the balloon's helium volume (0.25 ft³ for 9", 0.5 ft³ for 11"), where 0.85 covers real-world valve loss.

A 9-inch latex balloon holds about 0.25 cubic feet of helium, an 11-inch holds about 0.5, a 16-inch holds about 1.5, and an 18-inch foil holds about 0.5. That is why one 16-inch balloon uses roughly the same gas as six 9-inch balloons — big latex balloons are the fastest way to empty a tank.

For under ~50 balloons a disposable tank ($35-$70) is simplest and needs no deposit. Once you cross ~75-100 balloons, a small rental cylinder (55 ft³, ~$45-$75 plus a refundable deposit) fills far more per dollar. For 150+ balloons a large rental cylinder is the clear winner. The calculator above compares both paths for your exact count.

No. Balloon arches and organic garlands are air-filled on a frame — helium adds cost and makes them harder to build without any visual benefit. Use helium only for floating balloons and bouquets. If you are planning an arch instead, use our balloon arch calculator for the air-filled balloon count.

An 11-inch latex helium balloon floats about 12-18 hours indoors before it starts to sink, less in heat or a drafty room. Treating latex with Hi-Float sealant extends that to several days. Foil (Mylar) balloons hold helium far longer — 3 to 5 days — so fill latex the morning of the party and foil a day ahead is fine.

For 100 nine-inch latex balloons you need about 2 jumbo disposable tanks (each fills ~50) or a single small rental cylinder (55 ft³ fills roughly 187 nine-inch). For 100 eleven-inch balloons, plan on about 4 jumbo disposables (each fills ~25) or one large rental cylinder. A rental is almost always cheaper and less wasteful past the 100-balloon mark.

Disposable tanks are sold at party stores, big-box retailers, and craft stores, and online. Rental cylinders come from party-supply rental shops, welding-gas suppliers, and some grocery/florist counters. Reserve rentals 2-3 days ahead around graduation season and holiday weekends, when helium supply tightens and tanks sell out.