Balloon arch & garland calculator

How to calculate balloon quantities

1. Measure a string along the intended balloon centerline, including any covered tails. For a geometric model, enter the width of a half-circle and optional total height with straight legs.
2. Choose classic four-balloon clusters with an actual inflated diameter, or organic garland with your own total density or a representative sample.
3. Set whole color slots or size/color percentages, review the editable spare allowance, then optionally enter stock and pack sizes for each product.

What this calculator includes

• Classic clusters and organic garlands have separate methods; the organic method does not assume a universal number of balloons per foot.
• Size and color quantities conserve the whole build count. Spares are distributed once across products; stock and packs stay with each size/color combination.
• Convert units without changing the underlying estimate, then copy or print the current complete plan.

Measure along the garland, not across the opening

For a half-circle of centerline width W, covered length is πW/2 and rise is W/2. Adding straight legs to total height H gives πW/2 + 2(H−W/2), with H at least W/2. These models cover those shapes only; use a measured path for asymmetric designs, partial coverage or full circles.

The classic supplier convention is 4.8L/D with matching units. Divide by four, round up the cluster count, then multiply by four. Four color slots describe quantities per cluster. An 11-inch packet inflated to 8 inches must use the actual 8-inch diameter.

For organic designs, multiply path length by your total balloon density, or by sample balloon count divided by sample length, and round upward once. Count every size in the sample. Changing the size mix or packing means the old density may no longer be representative.

Allocate organic totals to sizes, then colors, using integer largest remainders. Every size uses the same color percentages. Allocate one rounded spare total across all build rows. Round new packs separately after stock deduction; stock of one product cannot cover another.

Worked balloon and pack examples

Classic: a 3 m path and 30 cm inflated diameter give 12 clusters and 48 build balloons. Color slots 2/1/1 give 24/12/12. A 10% reserve is five balloons, distributed 3/1/1: required quantities are 27/13/13, totaling 53.

Organic: 3 m at 40 balloons/m, or a 40-balloon sample over 1 m, needs 120 build balloons. Size shares 60/30/10 give 72/36/12. Color shares 50/30/20 give rows 36/22/14, 18/11/7 and 6/4/2. Twelve spares make the total 132.

Stock and packs: for the classic requirements 27/13/13, stock 7/0/3 leaves 20/13/10 still needed. Pack sizes 10/10/25 require 2/2/1 packs: 65 new balloons and 22 surplus balloons. Existing stock used is 10.

Separate packs: the nine positive organic size/color rows require nine 50-balloon packs with no stock. That buys 450 balloons for a requirement of 132, leaving 318 from the new packs. A pooled three-pack calculation would ignore the products.

Limits and assumptions

Actual consumption varies with inflation, packing and design. These are quantity estimates, not a guarantee of coverage. The editable 10% reserve is a starting assumption, not a universal allowance.

The tool supports four-balloon classic clusters and a common color mix across organic sizes. It does not optimize mixed kits, design spirals, estimate helium or assess frames and anchors. Build plus spares is limited to 50,000.

How your calculation data is handled

The calculator performs its arithmetic locally. It does not send measurements, labels, stock or summaries to an API, put them in URLs or save them in browser storage. Other page services may make ordinary requests.