Calculating number of balloons for a balloon ceiling.

First you need to determine the square footage of the balloons you will be using.  Each size has a different square footage. Below is the square footage of some typical balloons used:

1. A 9" balloon is about 0.56 sq ft (9"x9" = 81 sq in, then convert to it sq ft)
2. A 11" balloon is about 0.84 sq ft (11"x11" = 121 sq in, then convert it to sq ft)
3. A 16" balloon is about 1.78 sq ft (16"x16" = 256 sq in, then convert it to sq ft)

Many balloon decorators deduct about 20% of the square footage of the balloon since they may be exactly 9, 11, or 16 inches apart as they usually nestle into one another. 

Calculate the ceiling area by multiplying the length by the width in feet. For example, a 15' by 20' room would be 300 sq ft of ceiling space to cover with balloons. 

1. Divide ceiling sq ft by balloon sq ft.  For example, if you will be using 11" balloons (0.84 sq ft) to fill a ceiling that is 300 sq ft you will use the equation: 300/0.84 = 357 balloons.  
2. This calculation is for one single layer of balloons on the ceiling.  If you wish to have more balloons to overlap one another, you should multiply the total number of balloons needed by 1.5 or by 2.  

Always have extra balloons.  We recommend at least 10% more balloons than you calculated.

Ensure the ceilings are smooth and void of rough edges which may pop the balloons.  Also keep balloons away from warm lights so that they do not pop later on. 

1. If you do not want to cover the entire ceiling, you can create a barrier (see Figure 1 below) or a ring of balloons attached together with tape.  Then you may fill the centre of it with the loose balloons. You can even use this to keep the balloons away from warm ceiling lights. 
2. If you wish to tie ribbons to the ends of the balloons, keep in mind the height they will be as not to interfere with people walking through or other event activities.  

Figure 1. Frame of balloons if you wish to fill a specific area instead of an entire ceiling area.