There are numerous synonyms for the word "add up" that can come in handy in different situations. One such synonym is "total", which implies ascertaining the sum of multiple numbers or quantities. Similarly, "sum up" or "tally" can be utilized to indicate a result arrived at by adding numbers or amounts. "Accumulate" is another synonym that signifies the gradual buildup of something, be it financial assets or knowledge. "Count" and "reckon" can also represent the act of adding up and evaluating numbers. Furthermore, "compute," "estimate," and "calculate" are other synonyms used in various contexts to convey an addition or calculation.