The term "in-calculable" refers to something that cannot be measured, counted or estimated. Thus, antonyms of this word would mean measurable, countable, determinable, or estimable. Something that is calculable has a fixed or known value and can be computed or figured out using a defined formula or method. The opposite of in-calculable would therefore be quantifiable or calculable, certain, definite or precise. These antonyms are important in different fields such as science, statistics, mathematics, economics, and research, where measurements and calculations are fundamental in making accurate predictions or solving problems.