The Physics of Balloon Inflation
Calculating the required helium for an advertising balloon is straightforward when you use the standard geometric volume formula for a sphere: Volume = 4/3 × π × r³.
Volume by Diameter
- 8ft Diameter (r = 4ft): Volume is approximately 268 cubic feet (~7.6 cubic metres). Typically requires 1.2 to 1.5 standard commercial 7m³ helium cylinders.
- 10ft Diameter (r = 5ft): Volume is approximately 524 cubic feet (~14.8 cubic metres). Requires approximately 2.2 to 2.5 standard commercial 7m³ cylinders.
- 12ft Diameter (r = 6ft): Volume is approximately 905 cubic feet (~25.6 cubic metres). Requires approximately 3.8 to 4.2 cylinders.
Always order one spare cylinder to cover minor top-ups on day 3 or 4 of a multi-day campaign.