How many balloons does a helium tank fill?

A small disposable tank fills about 30 standard 11-inch latex balloons. Medium tanks fill around 50, and large tanks fill about 100. Foil balloons use more helium per balloon - roughly 40% more than standard latex. Always buy slightly more capacity than you think you need.

How long do helium balloons last?

Standard latex helium balloons last 8-12 hours. Foil (mylar) balloons last 3-5 days. Using Hi-Float sealant can extend latex balloons to 24+ hours. Inflate latex balloons no more than 2-3 hours before the party. Foil balloons can be inflated the day before.

Is it cheaper to buy or hire a helium tank?

Disposable party tanks cost £20-£40 and fill 30-50 balloons. Hiring a large refillable tank from a party shop costs £30-£60 for 100+ balloons. For over 50 balloons, hiring is usually better value. Under 20 balloons, buying pre-filled from a party shop may be cheapest.

Are helium balloons safe for kids parties?

Helium balloons are safe but supervise young children. Deflated or burst balloons are a choking hazard for under-3s. Never let children inhale helium. Tie balloons securely to weights so they do not float away. Collect all balloon debris after the party.

Helium Balloon Calculator — Tank Size & Quantities

Work out helium tank size and balloon quantities for your party.

Standard Latex Balloons

Balloon quantity or type

Foil Balloons

Balloon quantity or type

Tank Size

Total fuel tank capacity

Tank Cost

Amount in pounds sterling

Balloon Cost Each

Balloon quantity or type

Ribbon / Weights Cost

Amount in pounds sterling

How We Calculate This

This calculator estimates helium tank requirements based on balloon quantities and types.

Formula

Helium needed = (standard x 14L) + (foil x 20L)
Effective balloons = standard + (foil x 1.4) for tank sizing
Tanks needed = effective balloons / tank capacity
Grand total = tank cost + balloon cost + ribbon

Frequently Asked Questions

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Last updated: February 2026

All calculations are estimates. Adjust quantities based on your guests and event type.