Managing your Amazon catalog requires more than just uploading products. Without proper ASIN and SKU control, your listings can turn chaotic. Errors can affect your stock, confuse customers, and reduce sales. This guide breaks down what ASINs and SKUs are, why they matter, and how you can manage them like a pro. Whether you’re launching your first product or scaling your store, this knowledge will protect your business and boost performance.
What Is an Amazon ASIN?
An ASIN is the Amazon Standard Identification Number. It’s a 10-character code that Amazon uses to identify every product in its marketplace.
Each product has a unique ASIN. Even small variations, like color or size, get their own.
Where to Find an ASIN:
- In the product’s URL
- Under the product details section on a listing
- In Seller Central under your catalog
Why ASINs Matter:
- They help Amazon group similar products on one page.
- They organize your catalog.
- They allow customers to find your product easily.
Quick Tip: Books use ISBNs instead of ASINs.
What Is an Amazon SKU?
A Stock Keeping Unit (SKU) is a code you create to track products in your inventory. Unlike ASINs, which Amazon assigns, SKUs are defined by you.
You can create SKUs that include:
- Supplier names
- Product category
- Size
- Color
- Condition
- Price
For example: RA-TSHRT-BLK-M-15D might mean Royal Apparel Black Medium T-Shirt priced at $15.
Key Differences Between ASIN and SKU
| Feature | ASIN | SKU |
|---|---|---|
| Created by | Amazon | You |
| Purpose | Identify product in Amazon system | Track and manage your stock |
| Length | Always 10 characters | Customizable (8–20+ characters) |
| Global use | Unique per Amazon marketplace | Unique per seller |
How to Create an ASIN
You only need to create a new ASIN when your product doesn’t already exist on Amazon.
Steps to Create a New ASIN:
- Go to Seller Central
- Hover over Catalog, then click Add Products
- Enter the GTIN (UPC, EAN, or ISBN)
- If Amazon doesn’t find the product, click Create a New Listing
- Fill in product details like name, brand, variation, and description
- Add images, set your price, and choose your fulfillment method
- Submit your listing
Amazon will assign a unique ASIN once your product is approved.
How to Match an Existing ASIN
If your product already exists in the catalog:
- Search by product name, ASIN, or barcode
- Find your item in the results
- Click Sell this product
- Choose the condition (new, used, etc.)
- Add your offer details (price, quantity, fulfillment)
- Submit
This connects your product to the existing ASIN.
How to Create a Custom SKU
SKUs help you manage inventory with clarity and control.
Steps:
- Log in to Seller Central
- Click Catalog > Add Products
- Choose your product
- In the listing form, assign a custom SKU
Tips for Naming SKUs:
- Start with supplier initials
- Add product type or category
- Include size or color codes
- Add condition or price information
Example: AB-SHOE-BLU-42N-40D = Alibaba, Shoe, Blue, Size 42, New, $40
Why You Should Customize SKUs
Custom SKUs make it easy to:
- Locate stock quickly
- Track variations
- Understand sales performance
- Simplify returns
- Launch ads for specific products
- Reduce errors during fulfillment
Using custom SKUs helps in long-term catalog clarity.
Managing Product Variations with ASIN and SKU
You may sell products with different sizes, colors, or versions. Each variation must have its own SKU, but all can share the same ASIN.
Best Practices:
- Keep the same ASIN to preserve reviews and rankings
- Create a new SKU for every variation
- Hide the new SKU until old inventory sells out
- Switch listings smoothly to avoid customer confusion
When to Duplicate ASINs and SKUs
Sometimes, duplication is needed for logistics.
Examples:
- A SKU is bugged and can’t ship inventory
- You want separate SKUs for FBA and FBM
- You’re transitioning to a new package or version
Tip: Add a suffix like “-NEW” to differentiate duplicated SKUs.
Merging ASINs and SKUs
You can merge duplicate ASINs to boost ranking and share reviews.
Benefits:
- Reduces duplicate listings
- Increases customer trust
- Consolidates reviews and ratings
Important: Always merge into the ASIN with the most reviews and sales.
Fixing Catalog Errors
You may face issues like:
- Barcode conflicts
- Title conflict errors
- Parentage reviews not combining
- Incomplete listings
Fixes:
- Recreate SKUs with different suffixes
- Change titles in small steps
- Align product data using Category Listing Reports
- Complete missing fields in drafts
- Contact Seller Support when necessary
How to Backup Your Catalog
Don’t risk losing your catalog data. Backups are essential.
Steps:
- Go to Reports > Inventory Reports
- Select Category Listings Report
- Request and download
- Save to Excel or Google Drive with a clear date
When to Backup:
- Before large updates
- Every 10–14 days
- Before fixing listing issues
Best Practices for ASIN and SKU Management
Inventory Management
- Give every variant a unique SKU
- Use consistent SKU naming rules
- Update inventory levels regularly
- Use Amazon FN SKUs for better tracking
- Ship one SKU per shipment when possible
Sales and Marketing
- Optimize ASIN listings with keywords and images
- Create SKU-level ad campaigns
- Adjust discounts by SKU performance
- Track sales and conversions by ASIN
- Categorize ASINs by growth stage: Emerging, Flagship, Longtail
Customer Service
- Match ASINs to the right products
- Train staff to resolve SKU-based queries
- Set clear return instructions per ASIN
- Track returns by SKU for insights
FAQs on Amazon ASIN and SKU
No. Every product needs an ASIN to be listed.
Only if they are the exact same product and variation.
Yes, if your product does not already exist on Amazon.
Yes. You can and should customize SKUs to suit your operations.
No. ASIN is created by Amazon. SKU is created by you.
Yes, Amazon distinguishes between uppercase and lowercase.
Many do, but not all. Format can vary.
No. You must create a new listing to change the SKU.
No. Every SKU should be unique for tracking purposes.
UPC is a universal barcode. SKU is your internal tracking code.
Yes, this is useful for FBA and FBM listing separation.
Your inventory system should be SKU-based to track stock by variation.
Major changes to product titles that differ too much from the original.
Ensure product types and categories are identical in backend data.
Every two weeks or before any major update.
Edit the listing, update the variation, and save changes.
It’s a fulfillment SKU generated by Amazon for FBA items.
Yes, and it’s often recommended for better tracking.
Optional. It can help in sales tracking and planning.
You can fulfill through FBM if you have a separate SKU listed.
Yes. If multiple sellers offer the same product, they share the same ASIN but have different SKUs and listings.
You can, but it’s better to use unique SKUs per marketplace to avoid confusion.
It can link your product to an incorrect listing. Always verify before submitting. Edit or delete the listing if needed.
Tools like Amazon Seller Central, Inventory Lab, Helium 10, and Jungle Scout are widely used for catalog management.
You cannot delete an ASIN from Amazon, but you can delete your offer and stop selling it.
It depends on your system. Short SKUs are easier to scan, while longer SKUs may include more useful data.
Avoid special characters and spaces. Stick to alphanumeric characters, underscores, or hyphens for best results.
If two listings are too similar, Amazon may merge them to improve the shopping experience.
Enroll in Amazon Brand Registry, and monitor your listings regularly for unauthorized changes.
Contact Seller Support with detailed information and request a catalog update to merge ASINs.
Conclusion: Master ASIN and SKU to Succeed
Success on Amazon starts with solid catalog management. By understanding and using ASINs and SKUs properly, you’ll:
- Improve search visibility
- Prevent errors
- Maximize sales
- Make inventory tracking easy
Don’t treat catalog organization as a one-time task. Treat it as a system. With good practices, consistent backups, and smart naming, you’ll set your Amazon business up for long-term growth and control.
Whether you manage your own listings or work with experts, staying on top of your ASIN and SKU strategy is the key to thriving on Amazon.