The amount of computer time the program needs to run it to completion. is known as Time complexity.
The amount of memory it needs to run to completion is known as Space complexity .

Time complexity is the amount of time taken by an algorithm to run as a function of the length of the string representing the input. For example, if the time required by an algorithm on all inputs of size n is at most 5n3 + 3n, the asymptotic time complexity is O(n3).
Space Complexity of an algorithm is total space taken by the algorithm with respect to the input size.