General:
* Hand calculator
* Pocket calculator
* Slide rule (a more specialized tool for multiplication and division)
* Abacus (a very ancient manual calculating device)
More Specific:
* Adding machine (for basic arithmetic operations)
* Calculating machine
* Arithmometer (a historical mechanical calculator)
* Logarithm table (a pre-electronic tool for complex calculations)
The best word to use depends on the specific context. For example, "hand calculator" might be the most appropriate for a general description, while "adding machine" would be more specific if you are talking about a calculator designed for basic arithmetic.