Hello fpsgroup,
Yes, we can help you to build your wordpress website including the calculator API things and all.
Kindly share your requirements in details so that I can get a clear idea about the total scope of the job.
We have very good experience in website designing and development using WordPress, PHP, CodeIgniter, CakePHP, Laravel, MySQL, Ajax, HTML5, CSS3, Bootstrap, jQuery, JavaScript etc...
Let's discuss more details...
Regards
Sukant