PartyCalcs.uk
Balloon Arch Calculator — Balloons for an Arch or Garland
Estimate how many balloons you need for a balloon arch, garland, or column display.
Extra for popping and replacements
How We Calculate This
This calculator estimates balloon quantities based on arch dimensions and type.
The formula
Arch & garland balloons = garland length (m) × 24 balloons per metre (6 cluster points per metre × 4 × 11" balloons per cluster), matching the ~26 balloons-per-metre organic-garland convention.
Garland length is worked out from your width and height: a standard doorway arch uses π × (width ÷ 2) for the semicircular span, a full floor-to-floor arch goes up one side, across the top and down the other (width + 2 × height), and a half garland follows the span it is draped across.
Columns are different: a spiral column is built ~4 balloons per tier with ~1 tier per foot of height, so a pair of columns needs about 4 balloons per 30 cm of height per column — not the garland density.
Balloons are split into 3 sizes: 15% large (40cm), 60% medium (28cm), and 25% small (13cm) for an organic look. A 20% spare allowance is recommended on top, as arches need many balloons and popping is common — so the three size buckets add up to the base count and the spares are shown separately.
Frequently Asked Questions
A standard doorway arch (about 2.5m wide) needs roughly 100-150 balloons depending on how full you want it. Use a mix of sizes — large, medium, and small — for a professional organic look.
Allow 1-2 hours for a simple arch and 3-4 hours for a large organic arch. Using a balloon strip (arch tape) speeds things up considerably. Inflate balloons in advance and store in bin bags.
You need balloons in multiple sizes, balloon arch strip tape, a hand pump or electric inflator, fishing line or string, and something to anchor the ends (balloon weights, sandbags, or hooks). Glue dots help attach smaller balloons.
Latex balloons pop faster in direct sunlight and heat. A well-made arch lasts 2-3 days indoors or 6-12 hours outdoors in warm weather. For outdoor events, build the arch as close to the event time as possible.
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Last updated: February 2026
All calculations are estimates. Adjust quantities based on your guests and event type.