I understand that you would like a formula with dynamic data, but with no possibility of storage, for instant conversion purposes only.
If this is true, my proposal follows:
Day 1
1) Analysis of the formulas and structure of the table file
2) Depending on the complexity of the file I get the price
3) Creation of gmail to acquire PWA quotas free
4) PWA creation and integration with hosting
Day 2
5) Creating logic in Javascript and HTML
6) Definition of style and responsiveness with CSS
Day 3
7) Total versioning in BITBUCKET with GIT
8) Beta Calculator Testing
9) Final corrections