I do not have any excel spreadsheets for a rebound hammer test, but others may be able to help if you indicate what information you are trying to convert for a rebound hammer test.
Why do you want to use a compressive strength conversion for a rebound hammer? It is not accurate for that. Use it only for consistency of the strength values...not for the actual values.
Ron. I understand that the accuracy of the compressive strength is limited with this test. This test was used to check uniformity across a slab. I was just using the average to show the estimated psi average. I was looking for an excel program to put the numbers into rather than converting everything from the table on the side of the rebound hammer.