On average, it takes a standard tray of ice cubes about four hours to freeze completely. However, that time can differ greatly depending on a number of factors.

Ice freezes from the outside in, so the size and shape of the cubes can make it freeze much faster or slower. Large cubes with more volume will take longer to freeze.

Conversely, small ice cubes can freeze in as little as an hour since more of their total surface area can be affected by the cold all at once. Another factor is the freezer itself.

Water freezes at 32°F. Most freezers are set to 0°F, but if your freezer is faulty and can’t consistently get to that temperature, it’s less likely that your ice will solidify.

Speed up freezing by underfilling your tray as less water will lead to faster freezing. You can also opt for a metal tray, as it conducts temperature faster than plastic or silicon.

For best results, fill the ice cube tray with either very hot or very cold water, turn the freezer temperature down a few notches, and keep the door shut as much as possible.