Availability is the product attribute in your Google Merchant Center feed that tells Google whether an item can be bought right now. It takes one of four values: in stock, out of stock, preorder or backorder. Google uses it to decide whether to show the product in Shopping ads and free listings, and checks it against what your product page says.
How availability works
Every product in your product feed must carry an availability value. Most shop platforms, such as Shopify or WooCommerce, fill it automatically from your stock level. In stock means the item can be ordered and dispatched normally. Out of stock means it cannot be bought today. Preorder is for items not yet released, and backorder is for items temporarily unavailable but still orderable for later dispatch. Both preorder and backorder also need an availability date telling shoppers when the product will be ready to ship.
Google crawls your product pages and compares what it finds with the feed. It reads visible text such as “Out of stock” and your product structured data. If the feed says in stock but the page says sold out, Google flags a mismatch. With automatic item updates switched on in Merchant Center, Google can correct the value itself; without them, it may disapprove the item.
Products marked out of stock are not shown in Shopping ads. They remain in Merchant Center and come back automatically once the value returns to in stock.
Why it matters
Paying for a click to a product that cannot be bought is pure waste, and the shopper leaves annoyed. Accurate availability stops that spend and protects your conversion rate, which Smart Bidding relies on to value future clicks.
Repeated mismatches cause bigger problems. Items get disapproved and drop out of ads at exactly the moment stock comes back, and a pattern of inaccurate data can lead to account-level warnings. For a UK retailer heading into Black Friday or Christmas, when stock moves fastest, a feed that updates once a day may be hours behind the shop.
Preorder and backorder also carry customer-service weight. Under the Consumer Rights Act 2015, if no delivery time is agreed, goods should arrive within 30 days. Showing an honest availability date sets the right expectation and avoids refunds and complaints.
Common mistakes
- A feed that refreshes daily while stock changes hourly, causing frequent mismatches.
- Product pages showing “In stock” in theme text when the variant chosen by default is sold out.
- Structured data hard-coded as InStock on every product page regardless of real stock.
- Using preorder or backorder without an availability date, which leads to errors.
- Deleting sold-out products from the feed instead of marking them out of stock, which loses their history.
How to act on it
Open the diagnostics in Merchant Center and filter for availability issues. For each, compare the feed value, the visible page and the product schema, and fix whichever is wrong at its source. Switch on automatic item updates for availability as a safety net, not as the main fix.
Then check how often your feed refreshes. If you sell fast-moving stock, ask your platform or developer about more frequent feed fetches or a direct connection through Google’s Merchant API. If out-of-stock products still draw spend in other ways, I look at feed health and campaign set-up together when I manage Performance Max and Shopping campaigns. See also out-of-stock handling for the SEO side.