Helium Balloons Calculator
Work out how much helium is needed to float a number of balloons and how much weight they can lift.
Last updated · View algorithm, constants and default inputs (JSON)
About this calculator
Helium use and net lift are estimates for round latex balloons. Brand, actual inflation size, balloon weight, temperature, altitude, ribbons and payload change results; check the balloon supplier’s chart and leave a margin. Tank capacity is nominal and does not include filling losses.
Worked example
calculated with the default values below
Number of balloons 24 · Balloon size 11 inch · Helium tank size 14.9 cu ft (medium) Tanks needed 1 · Helium per balloon 0.500 cu ft · Total helium needed 12.00 cu ft · Total lift capacity 8.5 oz · Total lift capacity 0.53 lb · Lift per balloon 10.0 g
General background references
Disclaimer
These calculators give general estimates. Sizing, pricing, availability and standards vary by brand, retailer and country, so treat the output as a starting point and confirm it against the seller's or authority's own figures.
Implementation source
This record describes the implementation used by this page. It is not independent validation. External references, when available, support only the stated formula or definition; estimates and custom rules retain their own assumptions.
Formula and variables
V_total = 0.5×(d/11)³×n
- n
- Number of balloons
- d
- Balloon diameter, in
- V_total
- Total helium, ft³
- T_tank
- Tank capacity, ft³
Approximate round-latex net lift per balloon: 9 in 7 g, 11 in 10 g, 12 in 12 g, 16 in 34 g. Helium volume is estimated from a 0.5 ft³ 11-in baseline and scales with diameter³. Actual supplier/style values vary.
Frequently asked questions
How much lift do these balloon sizes provide?
These are approximate net-lift references for round latex balloons: about 7 g at 9 inches, 10 g at 11, 12 g at 12, and 34 g at 16. Supplier specifications vary by style and brand; the 16-inch figure is for standard round latex, not every shape. Allow for ribbons and payload.