Cost calculator for memorial plaques on building facades

We run a small workshop that produces memorial and dedication plaques for building facades — the kind used to mark historical events, honor notable residents, or commemorate an organization's founding. Right now every quote is worked out manually: sizes, material and design are clarified by phone or email, and only then does the client get a number. Because of this, a share of visitors leave the site before they ever see a price. We want a calculator embedded on the site so a visitor can configure a plaque and get an approximate price and production time right away.

The tool should let the visitor pick plaque dimensions from a preset list, with a custom-size option, choose the base material — granite, cast bronze or sheet metal — and select the inscription type: engraved text only, a portrait or bas-relief, or a combined design with an emblem. Mounting hardware and a protective coating should be optional add-ons shown as separate lines in the total. The result should show the calculated price, a production timeline in working days, and a short summary of the configuration for our manager to review.

Requirements:
— mobile-friendly interface matching our existing site design
— pricing formula configurable from an admin panel (base rates per material/size, per-option surcharges)
— form validation and a confirmation step before submission
— ability to send the quote to a manager by email or save it as a request