Hi there! I have checked out the excel file with the lookup tables and there are a few ways you can go about having this set up. Either PHP/AJAX, or just straight Javascript could do the trick. I do not have much experience with installing things into WordPress but I would be willing to find out if I was awarded the project.
The building of the scripts themselves, whichever route we take, should be simple enough and not very demanding. I have made several calculator tools previously, including a tool to calculate cost of taking a particular route drawn on a google map for yachts, depending on fuel consumption etc.
If you like my proposal, please drop me a message, even if I am offline, and I'll get back to you ASAP.
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British living in Manila - Website Applications Developer - PHP/MySQL / HTML/CSS/JQuery/AJAX/JS / SEO - 11 years experience building front-end and back-end for a global yacht charter company. I was the sole developer for 90% of that time. I also built my own online yahtzee (dice game) community with real-time games/chat which is still fairly popular today.
Some of the projects I have completed: booking systems, search/sales/accounts/management/CMS tools, file upload handling, image processing (sizes, adding text, grafting two images etc etc), on-the-fly PDF creation, automated emails with files attached, web-scraping (with/without login spoofing), email scraping, financial/accounts calculations/reports, complex management reporting, etc