Well, I haven't seen every origami crane in the world, but I reckon this one is pretty small!!
It's certainly the smallest Crane I've made, or any of my friends... I think it's possible to go smaller, but you would need very thin paper, tissue paper perhaps, and a magnifying glass. This strained my eyes quite a bit to make this one.
If you have made a crane smaller, or you have a picture of a smaller crane that you would like to share, upload it here!
There are pictures of tiny crane contenders here on the following page...