Build a Website

Hi, I have built a "application" within Excel which i would like converted to use as a website. I'd like customer to be able to log in and use the sites basic features, however, should they want more advance features to pay a subscription. The website will allow for user input to set a number of variables, which will then be used with the data stored in the DB's to generate a data set. The user can then save these for reference going forward. I already have hosting which includes webspace and databases, I have created some basic DB's but you may wish to build out something yourself. I have usually used PHP/MySQL as these are already configured on my webhost, but am open to other platforms if you feel are viable. This is just a POC currenlty, if the idea works out there will be further work to implement additional features and make the site look visually appealing. The POC build can just be basic and dosn't need a lot of visual design work.