How to use the balloon arch quantity calculator
- Choose whether you know the arch length or the width of a half circle. For a half circle arch the page works out the curved length for you.
- Enter the length or width, pick feet or meters, and enter your balloons per foot.
- Enter the number of colors. In More options, set the spare balloons percent, the balloons per pack and an optional price per pack.
- Read the headline for the balloons the arch needs, then the packs to buy and the split by color.
Formula
arch length = pi x width / 2 for a half circle, or the length you enter
balloons = arch length in feet x balloons per foot, rounded up
to buy = balloons x (1 + spare / 100), rounded up; packs = to buy / pack size, rounded up
Meters are converted at 3.28084 feet per meter. The colors are split as evenly as possible, with the leftover balloons going to the first colors.
A 10 foot arch at 40 balloons per foot
10 ft x 40 = 400 balloons. With a 10% cushion, 400 x 1.1 = 440. At 100 balloons a pack, 440 / 100 rounds up to 5 packs. Split across 3 colors, that is 147, 147 and 146 balloons.
A half circle arch 10 ft wide has a length of pi x 10 / 2 = 15.708 ft, which needs 629 balloons at 40 per foot and 692 with the cushion. An arch 10 meters long is 32.808 ft and needs 1,313 balloons at the same density.
Getting a balloons-per-foot number
The 40 per foot in the example is only an example. The real figure depends on balloon size, how many are in each cluster and how full the arch should look. The reliable way to find yours is to build one foot of the arch with your chosen balloons, count them, and enter that count.
Larger balloons cover more space with fewer pieces, and mixing sizes changes the count. If you use two sizes, run the page twice and add the results.
Buying by color
Packs usually hold a single color, so the table also shows the packs needed if you bought each color alone. That number can be higher than the overall pack count, since each color rounds up to whole packs. For the rest of the event, see the Party Planner Printable and the Party Food and Drink Quantity Calculator.
Assumptions and limits
- The count is length times balloons per foot, with no allowance for the shape of the base or the ends.
- The half circle length uses the width as the full diameter of the arch.
- The spare percent and pack size are examples and can be changed. Colors are split evenly.
- Helium, inflation time, wind and venue rules are not covered.
Frequently asked questions
How many balloons do I need for a balloon arch?
Multiply the arch length in feet by the balloons you use per foot. A 10 foot arch at 40 per foot needs 400 balloons, and about 440 with a 10% cushion for poppers and flawed ones.
How do I find the length of a curved arch?
For a half circle, the length is pi times the width divided by two. A half circle 10 feet wide has a curved length of 15.708 feet. Pick the half circle option and enter the width, and the page does this for you.
How many balloons are in one foot of an arch?
It varies with the balloon size and how tightly you cluster them. Build a one foot section, count the balloons and use that count. The 40 per foot shown is only an example to show how the page works.
Why does the color table show more packs than the total?
Because each color is rounded up to whole packs when bought alone. Three colors of 147, 147 and 146 balloons each need 2 packs of 100, which is 6 packs, while 440 balloons overall need 5.