Will this app support currency conversion from my theme or another app?

We follow the Shopify standards and conversion to allow compatibility among apps.

Shipping Rates Calculator uses the currency formatting defined in Shopify configuration, as described at  https://help.shopify.com/manual/payments/currency-formatting

The prices displayed are also enclosed in a standard <span class=money> HTML element.

That should allow currency converters to understand and convert the prices displayed properly but please note that converting prices is the responsibility of the currency converter tool and far from the scope of our app.