Which one do you need?
The split that matters most is how your class is graded, and it is written in your syllabus. If it lists category percentages — homework 20%, exams 50% — you are in a weighted class. If it lists a course total in points, you are in a points class. Using the wrong model is the single most common reason a calculated grade disagrees with the gradebook.
After that it is just a question of what you are asking. What do I need on the final is the home page. What is my grade right now is weighted or points. What did I get on that test is the test calculator. What is my GPA depends on whether you want one term, a weighted high-school average, or the full transcript.
None of them store anything. There is no account, no database, and no server that receives your grades — every calculation runs in your browser, and closing the tab discards it.