Pants and jeans come in many lengths, and there is a lot of confusion about the definitions of full-length, ankle, and cropped lengths. It doesn’t help when retailers sometimes classify lengths differently. I’m pedantic about lengths, so here are my definitions, which might differ from those used by other fashion professionals. Note that the definitions refer strictly to lengths, and not silhouettes.
Pants and jeans are full length, and sometimes called regular length, when they completely cover the ankle bone and ankle. Full lengths will vary from just covering the ankle bone and skimming the tops of shoes, to sweeping the floor and covering most of the shoe. Choose a full length that works for you and the type of footwear you like to wear with the bottoms.
Ankle pants and jeans showcase the ankle bone, and do not cover the ankle. That is the point of ankle pants. They are shorter than full-length pants. Hems usually finish right above the top part of the ankle bone when standing. Sometimes lengths partly cover the ankle bone, but personally, I find those a little long for ankle pants. They look more intentional when you showcase the full ankle. Otherwise it might look like you’re wearing full-length pants that are too short.
Cropped pants and jeans are any length shorter than full length. They can be cropped anywhere from right above the top of the ankle bone and up to six inches above it. Ankle pants are a specific type of cropped pant. Some people maintain that cropped pants are shorter than ankle length pants, but to me, anything that is shorter than full length is cropped.
The trick is to find your sweet spot for cropped pants. I’ve worn both shorter and longer cropped pants. I tend to like a length two inches above the top of my ankle bone when standing, depending on the silhouette and the shoes I wear with them. Sometimes I wear them an inch, or three inches above my ankle bone. Remember that when you cuff or roll the hems of pants and jeans, you are cropping their length too.
Feel free to ask questions in the comments if things are still not crystal clear.