PrestaShop combination price: variant price, price impact and EAN codes

How does PrestaShop calculate a combination's price?

A variant's final price is the product's base price plus the impact on price, and finally any sale. Take the Storm jacket with a base price of €199 including tax.

The last row is the most common mistake. Someone wants XXL to cost €219 and types that amount into the impact field. The customer sees €418 and gives up, and the statistics don't show why.

The second trap is tax excluded versus tax included. The impact field has a tax excluded and a tax included version, and B2B stores often think in prices without tax. Entering +20 in the wrong field gives a difference of the tax amount. A problem with the price impact combined with a unit price is described in a PrestaShop GitHub issue.

What happens to sales and price rises with variants?

A percentage sale is calculated from the variant's final price, while a fixed-amount sale takes the same amount off every variant. The surcharge in a combination is a fixed amount. When you raise the base price by 8%, XXL still costs only €20 more.

Let's work it out on the Storm jacket. A 10% sale on the whole product gives €179.10 for M and €197.10 for XXL. A fixed sale of minus €15 gives €184 for M and €204 for XXL. In both cases the difference between variants remains, but in the first it shrinks along with the discount. You can also set a sale on just one variant by choosing a specific combination.

If you are changing whole categories along with prices, read the piece on how to make a bulk price change. It also describes other combination traps.

Why does the product list show a different price from the product page?

Because the product list in a category shows the price of the default variant. If the default is XXL with a €20 surcharge, the whole jacket looks more expensive on the list than it is. The customer compares prices in the category and picks the cheaper product next to it.

The opposite problem happens too. The default is the cheapest variant, which has been sold out for months. The customer clicks a product at €199, and the only sizes available cost more. That's why the default variant should be in stock and typical, for example M in the most popular colour.

The same price goes into the product data for Google. A mismatch between the price on the list, on the product page and in the data is one of the reasons Google reports a price mismatch.

Why have an EAN and a reference for every variant?

Because for the warehouse, the wholesaler and Google, each size and colour is a separate item. Google Merchant Center groups the variants of one product and expects each to have its own data. This is described in the help on the item group ID. A variant without an EAN code is a common reason for disapproval. More on this in the piece on disapproved products in Merchant Center.

The attributes combinations are built from, such as size and colour, you create in the admin. This is described in the PrestaShop attributes documentation. The combinations themselves and their fields are in the product page, as described in the product management documentation.

How to check variant prices in your store

A few products with the most variants are enough.

1. Open a product with combinations in Catalog > Products and go to the Combinations tab.
2. Compare the impact on price with the supplier's price list. You are looking for amounts that look like a final price.
3. Check whether the amount was entered with or without tax. Work out one variant by hand.
4. Select each variant on the store page and compare the price with what you expect.
5. Check the default variant. It is the one shown on the product list and in the data for Google.
6. List the variants without an EAN and reference. You can fill them in with one batch.

How to fill in variant surcharges and EANs in batches

You describe the change for a group of products, and your chat (Claude or ChatGPT) shows each combination before and after. One change covers up to 100 combinations.