How do i display a value from excel data?

I've created a form that calculates the number of dates between trips. 

with this output value i need to reference another value in an excel sheet .. i.e. a vlookup

e.g. 1 days = 25, 2 days = 28 ...etc. 

how do i do this?

Unfortunately you would not be able to get the value from Excel to your jotform, but do you by some chance mean that you would like to set the vlookup function in the spreadsheet that you get after submissions (created by Google Spreadsheet integration)?