The phrase "unbelievable amount" refers to a quantity or number that is difficult to believe or comprehend. It suggests that something is so large or impressive that it seems unbelievable or hard to imagine. Full definition
Well, to start, this concept is being proposed by some really smart guys who have done unbelievable amounts of detailed research and calculations to make this recommendation. (newretirement.com)
Single - use - plastics are particularly problematic because they are often small, light enough to float and be transported by wind and water, and are produced in unbelievable amounts. (earthday.org)
Investors have lost unbelievable amount of money serving the greed of a few. (unovest.co)