Helium balloons float because helium is less dense than air. As the helium inside a balloon seeps out, the balloon will gradually deflate and eventually fall to the ground. The amount of time that a helium balloon will last depends on several factors, including the quality of the balloon, the size of the balloon, the amount of helium used, and the temperature of the surrounding air.

Good quality balloons made of latex or foil will typically last longer than balloons made of cheaper materials. Larger balloons will also last longer than smaller balloons since they hold more helium. The more helium that is used to inflate a balloon, the longer it will float. Finally, balloons will last longer in cooler temperatures since helium gas expands when heated.

In general, you can expect a helium balloon to last for anywhere from a few hours to several days. Some high-quality balloons may even last for weeks or even months if they are properly cared for. To help your helium balloons last longer, store them in a cool, dry place and avoid exposing them to sharp objects or heat sources.