Crate size

Well Cali is growing day by day and now he has grown out of his puppy crate which was a size medium 51x51x72. I just wanted to know what is the next best size to buy him? What size should I use? he is now 5 months should I get a large or XL, second hand crates are hard to come by in spain and also very expensive (70-150e) so i would like this one to be his second and last.
Please help. Thanks in advance.

I would go for the largest you can afford and fit. You can get ones which have a divider in so to make it smaller, and remove when you need more room.

I got outs a xl form day one and have had no issues.

Hope that helps.