SHOPIFYMICRO-SAASCUSTOM-WEB-APP

Shopify Product Area Calculator

We developed a Shopify application that bridges the gap between customer area requirements and per-package product sales.

16 Dec 2025

Shopify Product Area Calculator

The Vision & Challenge

An e-commerce retailer specializing in materials sold by area, like flooring and tiles, operates in a market where standard platforms create inherent friction. Customers plan projects in square feet, but products are sold in discrete units like boxes or pallets. This mismatch is a common point of failure for merchants in the construction and home improvement sectors.

The retailer found that this unit-versus-area problem was a direct cause of abandoned carts and costly ordering mistakes. Customers were forced to do manual calculations, often leading to confusion, under-ordering that delayed projects, or over-ordering that resulted in expensive returns. The standard Shopify product page was not equipped to handle this necessary translation, creating a poor user experience and impacting revenue.

Robust Devs was engaged to engineer a direct solution. We designed and built a micro-SaaS application that integrates a calculator into Shopify product pages. The tool gives customers an immediate, accurate answer to the question, "How many boxes do I need?", turning a point of friction into a moment of clarity and confidence.

Project challenges

  • The calculator needed to integrate into any Shopify 2.0 theme without custom code, appearing as a native feature of the store.
  • Business logic was complex, requiring a system that could manage unique area-per-package and wastage percentage rules on a per-product basis.
  • A secure, multi-tenant architecture was necessary to handle authentication and store distinct configurations for multiple merchants.

Solutions

  • We built a Shopify Theme App Extension using React. This allows merchants to place the calculator as a standard app block on product pages, ensuring compatibility and a native look across different store designs.
  • A merchant-facing dashboard was developed with the Shopify Polaris library. This provides a familiar interface for store owners to manage settings and define specific calculation rules for each product in their catalog.
  • A decoupled backend was built on Laravel and PHP to manage the Shopify OAuth flow and store merchant data in a MySQL database. This service provides a stable API for the front-end to perform calculations without affecting storefront performance.

Technologies used

We are concerned about the security and performance of our customers. That's why we always keep updating and use best technologies in our products

Front-end

JavaScript

ReactJS

HTML5

CSS3

Back-end

PHP

Laravel

DevOps

Docker

Github CI

Digital Ocean

Database

MySQL

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Real-time Quantity Calculation

The customer-facing widget allows users to input their required project area. It instantly computes the correct number of packages to add to the cart, automatically including the merchant-defined wastage percentage. This removes manual math, reduces user error, and provides immediate price transparency, building the confidence needed to complete a purchase.

Merchant Configuration Control

The partner has access to a dedicated dashboard that provides full control over the calculator's logic. Within an interface built on Shopify's own design system, merchants can set product-specific rules for area per package and wastage. This flexibility ensures calculations are accurate across a diverse product catalog, from tile to turf.