Drupal Commerce : Shipping Calculator for Shipping Service In my Product Add page, Seller can select Shipping service. I am using FedEx, USPS and UPS for my website.
Here there would be a link for shipping cost calculation.
By clicking on that link, it would open up a Shipping Calculator window from where Seller can add product dimensions and weight and select from available shipping services. By clicking on submit button, window would be closed and Selected Shipping Service and it's cost would be added into Textbox.

Is there any Shipping Cost calculator available in Drupal ?
I think you're looking for a module that do a very specific behavior, some shipping providers don't offer this option and if they do, maybe the drupal module doesn't implement it yet.

The basics of calculating shipping is knowing what the item measures and weights, for that you've got the modules Physical field and Commerce Physical product. With that you've got a field for dimensions and another one for weight, that would help you communicate with your shipping providers to get a quote before the user goes on with the checkout.


Commerce Fedex module seems to offer integration with the
physical modules mentioned above.
Commerce USPS also claims support for physical modules in the project description page
Commerce UPS also seems to provide physical module support.


Once you've got everything set up and your products have the information needed, you can start filtering out the shipping methods offered for every context and user. Depending on the visual requirement and behaviors you'll need to customize it further, but these collection of modules should provide a basic shipping calculation service.