Helium Balloon Lift Calculator (How Many Balloons to Lift a Load)

What this tool does

Helium lifts by displacing air that weighs more: lift per litre = (ρ_air − ρ_He) × g, with each density from the ideal gas law. At 20 °C and sea-level pressure that is just over 1 g of lift per litre, or about 1 kg per cubic metre — which is why lifting a person takes hundreds of party balloons, and why it should never be tried. Cold air gives slightly more lift and altitude gives less. A typical 11-inch latex balloon holds roughly 14 litres, but its own weight and the purity of the helium (party-grade gas is often not pure) take a few grams off the result, so the real figures are a little lower.

Formula

lift per litre = (ρ_air − ρ_He) × g, ρ = p M ÷ (R T) (M_air = 28.965, M_He = 4.0026 g/mol)

Variables

Symbol	Meaning	Unit
`v`	Volume of one inflated balloon	L
`tc`	Temperature	°C
`pk`	Pressure	kPa
`wb`	Weight of one empty balloon with its ribbon	g
`ld`	Mass you want to lift	g
`LG`	Lift per litre of helium	g/L
`LF`	The same as a force per litre	mN/L
`GL`	Gross lift of one balloon	g
`NL`	Net lift of one balloon (minus its own weight)	g
`NB`	Balloons needed for that mass	—

Worked example

Volume of one inflated balloon14 L
Temperature20 °C
Pressure101.325 kPa
Weight of one empty balloon with its ribbon3 g
Mass you want to lift100 g

Lift per litre of helium1.0377 g/L
The same as a force per litre10.18 mN/L
Gross lift of one balloon14.5 g
Net lift of one balloon (minus its own weight)11.5 g
Balloons needed for that mass9

Limitations

The formula assumes ideal conditions: no friction losses, no air resistance and no efficiency losses unless you enter them.
The result is an estimate based only on the values you type. Real situations often include factors this calculator does not know about.