There are several ways to tell if an avocado is ripe:

  1. Look at the color: A ripe avocado will have a dark green or almost black skin color. If it's still green, it's not yet ripe. However, some varieties of avocados, such as the Hass avocado, may also have a slightly brownish color when they're ripe.

  2. Check the texture: A ripe avocado should be firm but slightly yield to gentle pressure when you press it with your fingertips. If it feels hard, it's not yet ripe. If it's mushy, it's overripe.

  3. Check the stem: Gently remove the stem at the top of the avocado. If it comes off easily and the flesh underneath is green, the avocado is ripe. If the flesh underneath is brown, the avocado is overripe.

  4. Smell it: A ripe avocado will have a slightly sweet aroma, while an unripe one won't have much smell at all.

It's important to note that avocados can ripen quickly, so it's a good idea to check them often if you're waiting for them to ripen.