BalloonBuilder.com
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Work out how many balloons a helium tank fills, how much helium each balloon size needs, and what it costs per balloon. A free helium balloon calculator with EU and US tank presets, float times and helium/air mix — no signup.
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⚠ Volume note: Balloon volumes depend on the manufacturer — dimensions vary between brands, and the reported size (e.g. 12") may not always match the actual inflated diameter. Values shown are based on Sempertex (latex) and Grabo (foil) specifications.
⚠ Float time note: Float times are estimates and vary depending on balloon manufacturer, material weight, temperature, and altitude. For longer float times with latex balloons, consider using Hi-Float or similar balloon treatment products.
⚠ Party tank note: Disposable party tanks from some manufacturers may contain helium that is less than 100% pure (80% purity is common), which can reduce float time compared to professional-grade cylinders.
Always order 10–15% more helium than calculated to account for gas loss and inflation variations.
Our free Quote Builder includes a built-in helium calculator. Create professional balloon event proposals with material pricing, margin analysis, and PDF export.
Every image is a direct export from the BalloonBuilder design tools — only cropping was done after the export.
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Worth being straight about the difference before you judge one by the other.
This free helium calculator gives you gas volumes and tank counts. For full 3D previews, multi-size organic garlands, and exact manufacturer colours from Gemar, Tuftex, Sempertex, and Kalisan, explore the 3D design suite. (One subscription includes Arches, Columns, Garlands & Walls!)
The short version, one line each. Full tables, tank charts and the live calculator are above and below.
A 9-inch (23 cm) latex balloon holds about 7 litres (0.25 cu ft) of helium and floats for roughly 9 hours. A 20 L tank fills about 531 of them.
An 11-inch (28 cm) latex balloon holds about 11.5 litres (0.41 cu ft) of helium and floats for roughly 14 hours. A 20 L tank fills about 323 of them.
A 12-inch (30 cm) latex balloon holds about 15 litres (0.53 cu ft) of helium and floats for roughly 16 hours. A 20 L tank fills about 248 of them. In most catalogues 11″ and 12″ are the same balloon under two labels.
A 16-inch (40 cm) latex balloon holds about 42 litres (1.48 cu ft) of helium and floats for roughly 30 hours.
A 24-inch (60 cm) latex balloon holds about 110 litres (3.88 cu ft) of helium and floats for roughly 60 hours.
A 36-inch (90 cm) latex balloon holds about 340 litres (12.01 cu ft) of helium and floats for roughly 72 hours. A 36″ foil round needs far less — about 80 litres — because foil does not stretch.
Filling 100 standard 12-inch balloons takes about 1,500 litres (1.5 m³) of helium at 100% helium — roughly one 10 L cylinder at 200 bar.
Helium cost per balloon is the tank price divided by the balloons it fills. A €120 20 L tank filling 248 × 12″ balloons works out at about €0.48 per balloon. Enter your own tank price above for an exact figure.
Choosing between 9-inch and 12-inch: a 12″ balloon uses a little over twice the helium of a 9″ (15 L vs 7 L) and floats roughly 16 hours against 9. For a big display on a fixed gas budget, 9″ nearly doubles your balloon count.
A disposable party tank (about 400 L) fills roughly 25 × 12-inch balloons. A 10 L cylinder fills about 124, a 20 L about 248, and a 50 L about 620. All figures include a 7% loss factor.
Use this free helium balloon calculator to find out exactly how many balloons you can fill from any helium tank. Whether you're using a small disposable party cylinder or a professional 50-liter refillable tank, this helium calculator gives you accurate balloon helium counts based on manufacturer data from Sempertex and Grabo.
The helium volume calculator supports latex balloons (5" to 36" / 90 cm), foil balloons (18" and 36" rounds, hearts, and stars), number balloons (26" and 40" with individual digit volumes), letter balloons, and Globe/Orbz balloons. You can also enter a custom balloon diameter up to 240 cm for specialty sizes.
Save money by using this helium balloon inflation calculator to calculate your exact helium needs before your event. Mix helium with air (60/40 or 80/20) to stretch your tank further — the calculator shows you exactly how many more balloons you'll get with each mix ratio.
Use this helium tank calculator to find the right tank size for your event. In Europe, disposable party tanks are labeled by approximate balloon count ("20", "30", "50" balloons). Professional decorators typically use refillable cylinders from 10L to 50L at 200 bar pressure. A standard 20-liter tank holds 4,000 liters of helium volume — enough for approximately 250 standard 12" latex balloons.
In the United States, tanks are measured in cubic feet. Common sizes include disposable party tanks and rental cylinders from 20 to 291 cubic feet. This helium calculator lets you compare tank sizes and calculate the exact balloon helium count for each — helping you find the most cost-effective option for your balloon inflation needs.
Professional balloon decorators often use a helium/air mix to reduce costs while keeping balloons airborne. This helium balloon inflation calculator lets you see exactly how different mix ratios affect your balloon helium count. A popular 60% helium / 40% air mix lets you fill 67% more balloons from the same tank, though float time is reduced to about half. This is ideal for same-day events and indoor installations where maximum float time isn't critical.
At 50% helium, standard 11"–12" latex balloons will barely float. Below 40% helium, most latex balloons will not stay airborne. Use this free helium calculator to experiment with different mix ratios and find the optimal balance between cost and float time for your event.
This free helium balloon calculator tells you how much helium you need — but BalloonBuilder lets you design the actual decorations in 3D. Create stunning balloon arches, columns, organic garlands, and walls with full 3D visualization, real brand swatches (Gemar, Tuftex, Sempertex, Kalisan), and professional exports. (One subscription includes all 4 core apps!)
Explore 3D Balloon Software →Answers to the most common questions about balloon helium usage, tank sizes, and helium calculations.
A standard 20-liter refillable helium cylinder at 200 bar holds approximately 4,000 liters of helium. With 12" (30 cm) latex balloons, each requires about 15 liters — giving you roughly 248 balloons per tank after accounting for a 7% loss factor.
Quick reference: 11" balloons ≈ 323 per tank · 9" balloons ≈ 531 per tank · 16" balloons ≈ 88 per tank · 24" balloons ≈ 33 per tank.
For 100 standard 12" latex balloons at 100% helium, you need approximately 1,500 liters (1.5 m³). A 10L refillable tank (2,000 liters at 200 bar) covers this with room to spare.
Helium/air mix reduces usage: at 60% helium, 100 × 12" balloons only need ~900 liters. For 100 × 18" foil rounds, budget ~1,500 liters. Use the calculator above for precise numbers based on your specific balloon mix.
Helium/air mix inflates balloons with a blend of helium and regular air. A common ratio is 60% helium / 40% air, reducing helium consumption by 40% while still keeping balloons airborne.
Use it for same-day events and indoor installations. At 50% helium, standard 11"–12" latex balloons barely float. Below 40% helium, most latex balloons won't stay airborne.
Float times depend on balloon type, size, and helium purity:
• 9" latex ≈ 9 hours · 12" latex ≈ 16 hours · 24" latex ≈ 60 hours
• 18" foil ≈ 4 days · 36" foil ≈ 6 days · 19" globe ≈ 15 days
Hi-Float treatment extends latex float times significantly. Helium/air mix reduces float time roughly proportionally.
A standard 12" (30 cm) latex balloon requires approximately 15 liters (0.53 cu ft) of helium. This is based on Sempertex manufacturer data at recommended inflation diameter.
Other sizes: 5" = 1L · 9" = 7L · 11" = 11.5L · 16" = 42L · 24" = 110L · 36" = 340L. See the full reference table below.
Quick guide for 12" latex balloons:
• Small party (20–50 balloons) → disposable party tank
• Medium event (50–200 balloons) → 10L refillable (2,000L)
• Large event (200–500 balloons) → 20L refillable (4,000L)
• Professional install (500+) → 30L or 50L tank
Always order 10–15% more helium than calculated to account for gas loss during filling.
How much helium does each balloon size need? Use this table for quick estimates. Based on manufacturer data from Sempertex (latex) and Grabo (foil).
| Size (inches) | Size (cm) | Helium (liters) | Helium (cu ft) | Float time |
|---|---|---|---|---|
| 5" | 13 cm | 1.0 L | 0.04 | ~4 hrs |
| 7" | 18 cm | 3.0 L | 0.11 | ~6 hrs |
| 9" | 23 cm | 7.0 L | 0.25 | ~9 hrs |
| 11" | 28 cm | 11.5 L | 0.41 | ~14 hrs |
| 12" | 30 cm | 15.0 L | 0.53 | ~16 hrs |
| 14" | 36 cm | 24.0 L | 0.85 | ~20 hrs |
| 16" | 40 cm | 42.0 L | 1.48 | ~30 hrs |
| 24" | 60 cm | 110.0 L | 3.88 | ~60 hrs |
| 36" | 90 cm | 340.0 L | 12.01 | ~72 hrs |
| Type | Size | Helium (liters) | Float time |
|---|---|---|---|
| Round/Heart/Star | 18" (46 cm) | 15.0 L | ~4 days |
| Round/Heart/Star | 36" (91 cm) | 80.0 L | ~6 days |
| Number / Letter | 26" (66 cm) | 20.0 L | ~4 days |
| Number / Letter | 40" (102 cm) | 55.0 L | ~5 days |
| Globe / Orbz | 11" (28 cm) | 12.0 L | ~10 days |
| Globe / Orbz | 15" (38 cm) | 25.0 L | ~12 days |
| Globe / Orbz | 19" (48 cm) | 50.0 L | ~15 days |
Tank capacity varies by region — EU tanks are measured in litres at 200 bar, US tanks in cubic feet. Balloon counts below are for 12″ (30 cm) latex and include a 7% loss factor.
| Tank Size | Helium Volume | 12" Balloons per Tank | Best For |
|---|---|---|---|
| 2L cylinder | 400 L | ~25 | Small decorations |
| 5L cylinder | 1,000 L | ~62 | Home parties |
| 10L cylinder | 2,000 L | ~124 | Medium events |
| 20L cylinder | 4,000 L | ~248 | Large events |
| 30L cylinder | 6,000 L | ~372 | Professional work |
| 50L cylinder | 10,000 L | ~620 | Large installations |
| Tank Size (cu ft) | Helium Volume (L) | 12" Balloons per Tank | Best For |
|---|---|---|---|
| 14.9 cu ft (disposable) | 422 L | ~26 | Small parties |
| 55 cu ft | 1,557 L | ~96 | Medium parties |
| 80 cu ft | 2,265 L | ~140 | Medium events |
| 125 cu ft | 3,540 L | ~219 | Large events |
| 200 cu ft | 5,663 L | ~351 | Professional work |
| 291 cu ft | 8,238 L | ~510 | Large installations |
Three ways to get helium, and the break-even between them is mostly a question of how many balloons you inflate per year.
Disposable party tanks are the most expensive helium you can buy per balloon. A typical disposable holds around 400 litres — roughly 25 × 12″ balloons — and the cylinder is thrown away. Some brands fill them to less than 100% purity (80% is common), which shortens float time. Fine for a single party, poor value for a business.
Rental cylinders are the standard for working decorators. You pay a refill charge for the gas plus an ongoing cylinder rental, and you return the same cylinder to be refilled. Sizes run from 10 L to 50 L in Europe (2,000–10,000 litres) and 55 to 291 cu ft in the US. Because you are billed for gas rather than for packaging, cost per balloon drops sharply — the 20 L cylinder in the chart above fills about 248 × 12″ balloons against the disposable's 25.
Buying a cylinder outright only makes sense at volume, and in many countries the cylinder itself must stay with a licensed gas supplier for periodic inspection, so outright ownership is less common than decorators expect. Check what your local supplier actually offers before budgeting for it.
Whichever route you take, put the tank price into the calculator above and it will return your real helium cost per balloon — the number that belongs in a quote, and the one that tells you when rental starts beating disposables.
To master balloon décor, it helps to understand the science inside the balloon. Helium (He) is a noble gas and the second-lightest element in the universe — but why exactly does it make balloons float?
The air we breathe is a mixture of roughly 78% nitrogen (N₂) and 21% oxygen (O₂), with an average molecular weight of about 29 g/mol. A helium atom weighs just 4 g/mol — approximately seven times lighter than the surrounding air. This density difference creates buoyancy: the heavier air exerts a net upward force on the lighter helium, the same principle that makes a cork float in water.
In practical terms, one liter of helium at standard conditions can lift roughly 1 gram. That simple number is the foundation of every helium calculation a balloon decorator needs to master.
Despite being the second most abundant element in the universe, helium is surprisingly rare on Earth. The helium we use in balloons is a byproduct of natural radioactive decay: heavy elements like uranium and thorium, buried deep within the Earth's crust, have been emitting alpha particles (helium nuclei) for billions of years. This helium slowly migrates upward and becomes trapped in underground natural gas deposits, where it is extracted and refined.
Because helium is a non-renewable resource — once released into the atmosphere, it escapes into space — global supply fluctuates and directly impacts pricing for balloon professionals. This is precisely why accurate helium calculation is not optional; it is essential for running a profitable balloon business.
For professional balloon decorators, helium is one of the highest variable costs on every job. Guessing helium volume leads to two costly outcomes: wasted gas that erodes your margins, or insufficient gas that leaves you scrambling on-site.
Helium behavior is also highly sensitive to temperature. Gas expands in heat and contracts in cold — a latex balloon inflated in an air-conditioned workshop may look underinflated at an outdoor summer venue, or vice versa. Altitude also affects balloon performance: at higher elevations, the lower atmospheric pressure means balloons expand more and float longer, but may pop sooner.
Our Free Helium Calculator uses exact volume formulas based on balloon geometry to ensure you know precisely how much gas you need for every job — whether you are filling 11-inch latex rounds or 36-inch jumbo balloons. The result: accurate planning, protected profit margins, and zero guesswork.
📊 Data accuracy: Helium volumes and float times in this calculator are based on Sempertex manufacturer specifications (latex) and Grabo Helium Chart 2023 (foil, number, globe). A 7% efficiency loss factor is applied to all tank calculations to reflect real-world gas loss during filling.
🎈 Built by professionals: BalloonBuilder is designed by a professional balloon decorator with hands-on experience in helium management for events of all sizes. The calculator has been verified against real-world helium consumption data.
📅 Last updated: August 2026
Helium is only half the job. To work out how many balloons a structure needs, use the balloon calculator — it covers arches, columns, walls and ceilings. To design and visualise the structure itself, open the balloon arch maker.
BalloonBuilder is professional balloon design software with real-time 3D rendering, 15+ design modes, automated balloon counting, and export-ready client presentations. Plans start at $14.90/month.