Bloomberg:
Iran produces about 50 ballistic missiles a month, which is about half of its production capacity before the war. Iran is estimated to have at least 1,700 ballistic missiles in its inventory.
Israel estimates that Iran had about 2,500 ballistic missiles in stock before February 28. In addition, Iran fired at least 2,200 of these missiles during the war, suggesting that Iran has produced as many as 1,400 new missiles since then (or that Israel's estimates were inaccurate).
The report also indicates that Iran has "thousands" of Shahad-type weapons, and that at least 4,900 of these weapons were fired during the war.