Excel to Web App conversion

have an excel workbook that has a front end 20 questionbased input and 6 computing tabs that work to cross tabulate for a financial 3 year snap shot prediction year over year. I would like this to be made into an app that is easier to work across for others to use it as a web app for subscribers. The triggers used, tabulates the projected investments margin of profits as well; takes comparison analysis' - also use of web resources to populate data need to be integrated, this will be via api in the web app. Built practical, not full of pretty things :)