How to fetch the total value of summary report in an api ?

You could us a combo of API_GenResultsTable and some math in your code to add up the results.

But, there might be a more native way to get what you are looking for.  

What are you trying to do with that data, or where is it going?

hi Mathew,

i want to read the total value of the report. When i am doing the same calculation in my code page it is taking much time so to save that i just need the total value to show in my custom report.

Any reason you don't make a summary report if you just want the totals?  Not sure what you are trying to via API.  What is your end goal or use case?  There might be a better / cleaner way.