Short answer
Square is usually the cleaner starter for simple in-person selling; Shopify POS becomes more compelling when the Shopify online store is central to the business.
Processing rates, advanced inventory, staff permissions, hardware, add-ons, and ecommerce subscriptions can move the total far beyond the base POS fee.
Square
Small retail, service, mobile selling, and businesses that want fast setup.
Shopify POS
Retailers that need one product, customer, and order system across online and in-person sales.
Decision table
Put the same questions side by side.
| Factor | Square | Shopify POS |
|---|---|---|
| Best starting fit | Simple in-person and mobile selling | Omnichannel retail |
| Ecommerce role | Available, but not always the center | Core platform strength |
| Payments | Square payments ecosystem | Shopify Payments or additional-fee considerations |
| Inventory depth | Good starter; advanced needs may add cost | Stronger when Shopify catalog is already primary |
| Main strength | Low-friction setup | Online/in-store continuity |
| Main risk | Outgrowing starter workflows | Paying for a larger stack than the shop needs |
Run the numbers