You've decorated the room, the balloons look amazing… and by the next morning half of them are on the floor. If that sounds familiar, it's not you. Different balloons simply hold helium for very different lengths of time.
Typical float times
With Airloons 99.95% purified helium, indoors at normal room temperature, you can expect roughly:
- Latex balloons (9″–12″): 8–10 hours
- Standard foil balloons (18″): 2–5 days
- Jumbo foil balloons (36″): 5–7 days
- Letter/number foil (30″): 2–5 days
- Letter/number foil (20″): often too heavy to float at all
Why latex balloons come down sooner
Helium atoms are tiny, and latex is a natural material with microscopic pores. Over a few hours the helium slowly escapes through the rubber, the balloon shrinks a little and eventually it can't lift its own weight and string. Foil balloons are made from a metallised film that is far less porous, so the same helium stays inside for days.
Size matters too. Bigger balloons hold more helium relative to their surface, which is why a 36-inch foil balloon outlasts an 18-inch one.
Why some number balloons won't float
Smaller letter and number foils, especially 16″–20″, have a lot of foil and seams for the small amount of helium inside. Many are made to be filled with air and displayed on a stick or hung up. If you want floating letters, choose 30-inch or larger and check the pack says "helium quality".
How to make your balloons last longer
- Time your inflation. Fill latex balloons on the day, as close to the party as you can. Foil balloons can be done the day before.
- Keep them indoors and out of the sun. Heat makes the gas expand and can pop balloons; cold makes them shrink and droop.
- Don't over-fill. An over-stretched latex balloon has thinner walls and loses helium faster.
- Use good-quality balloons. Thicker latex holds helium noticeably better than thin, cheap balloons.
- Avoid rough surfaces. Ceilings with textured plaster, plants and heaters can puncture or warm balloons.
Planning the timing for your party
If guests arrive at 2pm, aim to finish your latex balloons around midday. They'll look full and bouncy all afternoon and well into the evening. Put up foil balloons the night before so you have one less job on the day.
Not sure how many balloons a canister will fill? See our guide: How Many Balloons Does a Helium Tank Fill?, or pick a size: 30, 50 or 70 balloons.