excel formula to find duplicates and sum their corresponding cells

The worksheet looks like this (pipe | for the next column):

Column A | Column B
jeff | 1
jeff | 21
lara | 4
mike | 300
mike | 500
kate | 6

I want a formula that will seek out duplicate values in Column A and then sum the values that exist in Column B for each duplicate.

In this example I would like my final result to show Jeff | 22 and Mike | 800

I am not very good with Excel but in English I would imagine the formula would play out something like this:
If Duplicate in Column A then Sum Column B (for cells with duplicate values)

Can this be done with an Excel formula or would VBA be required?