With current technology, a wafer is 10" in diameter (254mm), the aperture size limiting the die size is around 900 mm^2, so a chip is at most about 30x30mm. This would make it about 60-70 chips per wafer at maximum chip size (e.g. high end GPU). Most chips are a lot smaller, but there's a ballpark figure for you.

Chips are square but wafers are round, so there's a lot more wasted area with large chips.