Total-price generator to work out mileage for a booking

Hi all

Building a site for an event supplier. After recommendations for how best to add the ability for a potential client user to input the address of their event and have it calculate the total cost of delivery to that event (so that they can build in a + £/mile... + £/km).

Essentially - similar to WooCommerce Distance Rate Shipping.

Any recommendations for a Squarespace-hosted alternative?