To dream of a calculator represents carefully evaluating an issue or situation. You may want to make sure of something, consider alternative options, or reexamine beliefs and opinions.
A calculator may reflect doubts, or new developments that interest you in weighing or reconsidering choices.
Example: A young man dreamed of being given a calculator by a friend. In waking life he was planning on asking out girl he thought liked him before finding out that she didn’t. The calculator reflected the information he received that made he rethink his plans.