Difference Between SKU, PLU, and UPC
Three product codes and how they work together
Written by Michael Cook
Updated at May 6th, 2026
Table of Contents
This article shows you how SKU, PLU, and UPC codes are used when adding, searching, scanning, and managing products in the store so you can improve inventory accuracy and reduce checkout and product management errors.
Understanding UPC (Universal Product Code)
A UPC is the barcode number printed on a product by the manufacturer. It is the same number on every product, no matter which store sells it.
A Coca-Cola bottle sold at your store and at a competitor's store will have the same UPC. That number never changes.
What a UPC is used for:
- Scanning products at the register
- Identifying the exact product during receiving
- Linking a scanned item to the correct entry in your price book
What a UPC looks like:
0 49000 02890 4
UPCs are almost always shown as a barcode on the product packaging.
Understanding SKU (Stock Keeping Unit)
A SKU is a product code that your store or company creates. Every business can build its own SKU system, and no two stores need to use the same format.
SKUs are internal numbers. They are meant for your team, not the manufacturer or the customer.
What a SKU is used for:
- Searching for an item in your price book or inventory system
- Organizing products by category or vendor
- Tracking stock levels and generating reports
What a SKU looks like:
One store might use DRINK-COKE-500 for a 500 mL Coke bottle. Another store might use 100245. Both are valid — there is no universal standard.
Because your team creates SKUs, you can make them as readable or as structured as you need.
Understanding PLU (Price Look-Up Code)
A PLU is a short number used mainly for fresh produce and bulk items — products that do not have a barcode. Cashiers type the PLU into the register to identify the item and pull up the price.
What a PLU is used for:
- Identifying fruits, vegetables, and bulk foods at checkout
- Ringing up items that cannot be scanned
What a PLU looks like:
- Bananas =
4011 - Large lemons =
4053
PLUs are usually 4 or 5 digits. Many standard PLU codes are the same across stores because they are assigned by an industry organization, not by individual businesses.
How they work together
In XSite, a single product can have all three codes attached to it. When you add or update an item in your price book, you may be asked to enter the UPC (from the barcode on the package), a SKU (your internal tracking number), or a PLU (for produce items). The system uses whichever code applies to identify and manage that product correctly.
| Code | Created by | Used for | Typical format |
|---|---|---|---|
| UPC | Manufacturer | Scanning at register | 12-digit number / barcode |
| SKU | Your store | Inventory and search | Custom — letters and numbers |
| PLU | Industry standard | Produce and bulk items | 4–5 digit number |
Tips & Warnings
- A product can have more than one code. A packaged item might have a UPC for scanning and a SKU for your internal inventory tracking. Both can exist in the system at the same time.
- SKUs are yours to define. If your store does not yet have a SKU format, consider using something consistent — like a category prefix followed by a number. This makes searching and reporting much easier over time.
- PLUs are mostly for produce. If a cashier cannot scan an item, a PLU is usually the solution. If the item is not produce or bulk, check whether a UPC lookup or manual SKU entry is the right approach instead.
- Entering the wrong code in the wrong field causes lookup failures. If a product is not appearing when you scan it, confirm that the UPC saved in the price book matches what is printed on the package exactly — including any leading zeros.