I’m building a new Shopify store that sells floor and wall tiles and need the storefront to speak the language customers expect: prices shown per square meter, yet checkout handled strictly in full boxes. Each product will carry its own box coverage figure (for example, 1 box = 1.43 m²), so the theme has to calculate and display the correct square-meter rate automatically while the cart, inventory, and order remain tied to whole-box quantities only. What I’d like coded • Liquid / JavaScript edits (no third-party app) that read a metafield such as product.box_coverage and divide the variant price by that value to surface the per-m² price across product, collection, and search pages. • An on-page quantity input that lets shoppers type the square meters they need; the script rounds up to the nearest whole box, updates the price, and shows a quick note like “You’ll receive 5 boxes (7.15 m²).” • Cart and checkout must still pass the box quantity to Shopify so stock control and fulfillment stay accurate. • Storefront stays set to square meters; if I ever add square-feet products later, the code should allow an easy toggle via theme setting or additional metafield. Acceptance criteria – Correct per-m² price displayed everywhere a price appears. – Quantity rounding always produces whole-box numbers and never permits fractional boxes. – No impact on page speed greater than ±3 % on Shopify’s theme analyzer. – Clear hand-over notes showing where code was inserted and how to add new products / coverage values. If you have tackled similar unit-pricing challenges or have a neat, lightweight approach inside Shopify’s theme framework, I’d be happy to see how you would structure it.