SKU (Stock Keeping Unit) is a code tied to a particular product for internal use. Believe me, correct SKU is the very foundation of your store, you cannot mess with this one. These codes allow us to track our stocks and supplies and it helps a lot for listing in e-commerce marketplaces.
So, we must make an SKU that can be easily understood and used for faster listing in many kinds of marketplaces. Don't trouble yourself later because you have underestimated this. To get a correct SKU, you only need to apply these 4 simple rules:
This way you won't confuse yourself, the audience, or the spreadsheet. Symbols like ' / ' will sometimes cause format problems in your excel. While special symbols like ' @ ' or ' # ' become irrelevant when you use them in making SKU. And of course, don't use space.
Combine but don't mix when representing the information! Start with letters like the brand's of an item, because it's much easier to sort out later on.
Use one character for one variable. If you code the size of your items as number, like "15" for "S", do the same for "all size", don't write it as "ALL". You need some way to represent it, like "99" or whatsoever.
Make sure the SKU of an item is never used before. Yes it is unique, but please, double check your SKU. One item one SKU, even for the variations.
This is the most important thing, consistency. Make sure everyone who makes the SKU really understands your rules when making your store SKU. This way, even your customers will know how to use them when searching for your items.
Voila! That's all are our tips for correct SKU, I hope this will help you and whoever manages your store.