Well, it all depends on the type and size of saddle doesnt it? my horse is currently in a 46" girth and an 18" ideal saddle. - girth slightly too big at the mo.
My tb takes a 46" he's 15.3hh and the little wesh b that i had took a 40" and he was 14hh. He tended to gain afew pounds in the summer so went up a size
Mine has a 50" on her GP at the mo as she's feeling skinny... 52" is for the summer (but she was skinny last summer so I can see myself having to buy a 54" this year
)
32" on her dressage one.
She's a 15.3hh proper chunky middleweight ID X with a huge belly (just how she's built).
15hh Arab is in a 38' or 40' depending what we have under his saddle numnah-wise
16hh WB in a 46'
16.2 ID/TB in a 48' but could go to a 50' really.
They are all so different aren't they!