They get about 12 - 15 feet if you let them. I keep mine only as tall as I can reach and I have trained the lower branches horizontally (I planted 4 within 2' of each other and keep the inside branches either pruned or trained away from the center "light well." They are more like persimmon bushes than trees).
If you summer prune them to keep them shorter it may be a factor in bringing them to fruit sooner. I read it takes up to 5 years for persimmons to start fruiting but mine fruited the 2nd year and I got ~100 fruits by the 3rd year. Jiro is what is sold as Fuyu in this country.

Thanks, greenwitch!

I have seen really big ones but that is only if they are in really good soil with plenty of water.
Soil is a bit scarse at my place I have one tree planted on rock and it has only grown to about 6 foot tall in 15 years
It still has good fruit tho