A best seller sells out. Within a day the product page shows a grey “Sold out” button, paid campaigns keep sending clicks to it, and the people who wanted it leave for a competitor. When stock returns three weeks later, nobody knows how many sales were lost or who to tell.
Stockouts are a revenue problem first, but they are also a search and data problem. The page may lose its place in Shopping results, ads waste budget, and you lose the clearest demand signal you will ever get: people trying to buy something you do not have.
Pre-orders and back-in-stock alerts turn that moment into sales and data. This guide covers when to use each, how to set them up on the product page, in Google Merchant Center and in structured data, how to word delivery promises, how to handle payments and consumer rules, and how to use the sign-up data to plan your next purchase order.
What a sold-out button costs in revenue, ads and rankings
When a product goes out of stock, several things happen at once, and they compound.
- Lost orders. Visitors who cannot buy either wait, choose a substitute or leave. Without a sign-up form you cannot tell which.
- Wasted paid traffic. Shopping and Performance Max campaigns depend on feed availability. Search and social ads pointing at a sold-out page keep spending unless someone pauses them.
- Search visibility at risk. Teams sometimes respond by unpublishing or redirecting the product page, which throws away its rankings and links. Google advises against this for temporary situations.
- Missing demand data. Sales history stops at the stockout. A forecast based only on units sold will underestimate demand for next time.
“It's better to still allow that page, and mark it out of stock.”
— Google Search Central, Temporarily pause or disable a website
The rule of thumb is that a product coming back should keep its URL, its content and its price on the page. Our guide to out-of-stock and discontinued products covers the SEO side in more depth, including when a discontinued item should be redirected instead.
Choosing between pre-orders, backorders and back-in-stock alerts
These three tools are often lumped together, but they make different promises to the shopper and carry different risks for you.
| Option | What the shopper gets | Best when | Main risk |
|---|---|---|---|
| Pre-order | Places an order now for a product not yet released or restocked, with an expected ship date | You have a confirmed delivery from the supplier or a launch date | Missed dates lead to cancellations, refunds and complaints |
| Backorder | Orders an existing product that is temporarily out of stock; ships when stock arrives | Short, predictable restock windows | Shoppers may not realise their order will not ship immediately |
| Back-in-stock alert | Leaves an email or phone number and is notified when stock returns | Restock date is uncertain, or you want to measure demand first | Lower conversion than an order; some subscribers will have bought elsewhere |
| Sold out with nothing | Nothing | Product is discontinued and has no replacement | Lost sales and lost data |
A useful decision rule:
- Is the product coming back? If no, treat it as discontinued and link to alternatives.
- Do you have a confirmed date? If the supplier has confirmed shipment and you trust the date, offer pre-orders or backorders.
- Is the wait short and the margin healthy? If the wait is more than a few weeks, or margin is thin once payment fees and possible refunds are counted, use an alert instead.
- Are you still deciding whether to reorder? Use an alert. Sign-ups are evidence for the reorder decision, which we cover in our guide to validating product demand.
Setting up pre-orders on the product page, in Merchant Center and in schema
A pre-order has to be consistent in three places: what the shopper sees, what your product feed says and what your structured data says. Mismatches confuse shoppers and can trigger Merchant Center issues.
On the product page
- Replace “Add to cart” with “Pre-order now” so nobody mistakes it for an in-stock item.
- Show the expected dispatch date or window next to the button, not only in small print.
- Keep the price visible and state when payment will be taken (now, at dispatch, or a deposit now).
- If the cart can contain both in-stock and pre-order items, say clearly whether you will ship them together or separately.
- Show the same message in the cart, checkout and order confirmation email.
In Google Merchant Center
Google's product data specification lists four values for the availability attribute: in stock, out of stock, preorder and backorder. For pre-orders, it requires the date as well: “Provide the availability date [availability_date] attribute if you submit preorder [preorder]”. The date can be up to one year ahead, and an estimate is accepted if you do not have an exact date. The same specification states that “if an item is out of stock, the price must still be clearly visible on the landing page.”
“If an item is out of stock, the price must still be clearly visible on the landing page.”
— Google Merchant Center Help, Product data specification
In structured data
Google's merchant listing documentation supports several availability values in Offer markup. The ones that matter here:
| schema.org value | Google’s description | Use it for |
|---|---|---|
PreOrder | The item is available for pre-order. | Pre-orders with an expected date |
BackOrder | The item is on back order. | Temporarily unavailable items you still accept orders for |
PreSale | The item is available for ordering and delivery before general availability. | Early-access releases that ship before the general launch |
OutOfStock | The item is currently out of stock. | No orders accepted; alert sign-up only |
InStock | The item is in stock. | Back in stock (update promptly when stock lands) |
Google's documentation also says not to specify more than one availability value. Make sure your platform or app updates the markup automatically when stock status changes; a stale InStock on a sold-out page is a common cause of feed and rich result mismatches. Our Product schema and merchant listings guide covers the full Offer markup, and the Merchant Center disapprovals guide explains how availability mismatches are flagged.
Launching a new product before stock lands
The same logic applies to brand-new products. Google's guide to launching an ecommerce site suggests going live early with products marked as out of stock, and providing product data to Merchant Center “with stock marked as unavailable for purchase”, rather than hiding pages until launch day (Google Search Central). A product page that is already indexed, with a pre-order or waiting-list form, starts collecting demand and search history before the first unit ships.
Back-in-stock alerts by email and SMS that actually convert
A back-in-stock form is simple to add with most email and SMS platforms or a store app. The difference between a form that collects names and one that drives sales is in the details.
- Put the form where the button was. Replace the disabled add-to-cart button with “Email me when it’s back”. Hiding the form in a tab or footer kills sign-ups.
- Capture the variant. If the medium in blue is out of stock but the large is not, the alert must be tied to the exact variant. Our product variants guide explains why variant-level URLs and IDs matter.
- Ask for consent correctly. A back-in-stock request is consent for that alert. Adding the person to your marketing list needs separate, clear consent under most email and SMS rules.
- Send the alert as soon as stock is sellable, not when it arrives at the warehouse. An alert that leads to “Sold out” again destroys trust.
- Stagger sends when stock is limited. If 2,000 people are waiting and you have 300 units, alert in batches, earliest sign-ups first, so the last people do not click through to an empty shelf.
- Follow up once. A single reminder 24–48 hours later to non-buyers is usually enough. Stop after that.
- Track by SKU. Record sign-ups, sends, clicks and purchases for each variant.
SMS is effective for urgent, limited restocks because it is read quickly, but it carries stricter consent rules and higher costs per message. Our SMS marketing guide covers consent and frequency, and the ecommerce email marketing guide shows where back-in-stock fits among other automated flows.
| Alert element | SMS | |
|---|---|---|
| Speed of reading | Slower; may sit in inbox or promotions tab | Fast; usually read within minutes |
| Content space | Images, alternatives, sizing notes | One short message and a link |
| Consent rules | Consent for the alert; separate opt-in for marketing | Stricter in many countries; explicit opt-in and opt-out instructions |
| Cost per send | Low | Higher, per message |
| Best use | Most restocks | Limited drops and high-demand items |
Writing delivery promises customers believe
The most common pre-order failure is not the technology but the date. If you say “ships 15 March” and it ships 10 April, you will deal with cancellations, support tickets and refund requests, and you may breach consumer rules.
In the United States, the FTC's Mail, Internet, or Telephone Order Merchandise Rule (referenced in the FTC's advertising guide for small business) requires sellers to have a reasonable basis for any shipping time they state. If you cannot ship on time, you must tell the customer and offer the option to cancel for a refund. Other countries have their own delivery and cancellation rules, and in the UK the Digital Markets, Competition and Consumers Act 2024 gave the Competition and Markets Authority power to fine businesses up to 10% of global turnover for consumer law breaches, according to the CMA's April 2025 announcement. Treat dates as a legal promise, not marketing copy.
Wording that sets accurate expectations:
- “Expected to ship between 10 and 17 March. We’ll email you if that changes, and you can cancel for a full refund at any time before dispatch.”
- “Pre-order: payment is taken today. This item ships separately from the rest of your order.”
- “Back in stock early April (supplier estimate). Join the list and we’ll tell you the moment it’s available.”
Build a buffer into every date you publish. If the supplier says the container lands on 1 March, allow time for customs, receiving and picking before your stated dispatch date. For high-value or long-wait pre-orders, send a short progress email every few weeks. Good communication also reduces “where is my order” contacts, which are a hidden cost covered in our guide to trust signals for online stores.
Payment timing, authorisations and refunds for pre-orders
How and when you take money matters for cash flow, fees and disputes.
| Payment model | Cash flow | Customer experience | Watch out for |
|---|---|---|---|
| Charge in full at order | Best: cash before stock arrives | Simple, but customer pays before receiving anything | Refunds if dates slip; chargebacks on long waits |
| Authorise now, capture at dispatch | Neutral | Customer is not charged until shipping | Card authorisations expire after a limited period that varies by card network and processor |
| Deposit now, balance at dispatch | Partial | Lower commitment encourages more pre-orders | Second charge can fail; needs saved payment method and clear terms |
| Save card, charge at dispatch | Neutral | Feels like ordering from stock | Failed charges at dispatch; requires platform or app support |
Ask your payment provider how long an authorisation remains valid and whether your platform can save the card for a later charge. If you use buy now, pay later providers, check whether they support pre-orders at all; our guide to BNPL and payment options covers the wider trade-offs.
Count the costs before promoting pre-orders heavily. Payment processing fees on refunded orders are not always returned, chargebacks carry fees, and every cancellation costs support time. Our unit economics guide shows how to include those in contribution margin per order.
Turning sign-up data into the next purchase order
Back-in-stock sign-ups and pre-orders are the closest thing to measured unmet demand that most stores have. Use them in your reorder decisions.
A worked restock calculation
Example (hypothetical numbers). A skincare brand's best-selling serum sold out after 21 days. Before the stockout it sold 40 units a day. During the 18 days it was unavailable, 1,350 people signed up for an alert. From the brand's previous restocks, about 25% of alert subscribers bought within seven days of the alert.
- Expected orders from the waiting list: 1,350 × 25% ≈ 338 units in the first week.
- Normal demand over the next 60 days: 40 × 60 = 2,400 units.
- Demand lost during the stockout that will not come back: unknown, but at 40 a day for 18 days, up to 720 orders may have gone elsewhere.
- Reorder for the next 60 days: roughly 2,400 + 338 + safety stock, rather than 2,400 based on sales alone.
The conversion rate in this example comes from the brand's own history; yours will differ, so measure it on every restock. The point is that sales data alone hides the demand you could not serve.
What to track for every out-of-stock SKU
- Days out of stock and the date it sold out
- Alert sign-ups per day, by variant and traffic source
- Pre-orders placed, cancelled and fulfilled
- Alert-to-purchase conversion within 7 and 30 days
- Paid spend that went to the page while it was sold out
Questions retailers ask about selling stock they do not have yet
Should an out-of-stock product page be removed or redirected?
Not if the product is coming back. Keep the page live, show the price and an accurate stock status, and offer a back-in-stock alert or pre-order. Google's own guidance is to keep the page and mark it out of stock.
Is it better to take pre-orders or back-in-stock sign-ups?
Take pre-orders when you have a confirmed restock date, reliable supply and margin to cover payment and cancellation costs. Use back-in-stock alerts when the date is uncertain or you want to measure demand before committing to a reorder.
Should I charge customers in full when they pre-order?
It depends on lead time and risk. Full charge upfront is simplest for short waits. For long waits, a deposit or saving the card and charging at dispatch reduces refunds and chargebacks. Card authorisations expire, so check how long your processor holds one.
What availability value should a pre-order product use in Google Merchant Center?
Use preorder and provide availability_date with the expected date the product will ship. Merchant Center accepts a date up to one year in the future, and an estimated date if you cannot give an exact one.
How many people who sign up for back-in-stock alerts actually buy?
It varies widely by product, price and wait time, so measure it yourself. Track sign-ups per SKU, alerts sent, clicks and purchases within a set window such as seven days after the alert.
Fixing your next stockout before it happens
Pick your top 20 products by revenue and check what a shopper would see if each sold out tomorrow. Every one should keep its URL and price, offer either a dated pre-order or a back-in-stock form tied to the variant, update Merchant Center and structured data automatically, and feed sign-up numbers into your reorder plan. Doing this before the next peak is far easier than during it, especially if those products also feature on your permanent seasonal sale pages.
If you want help with product page set-up, feed availability or the email and SMS flows behind alerts, our ecommerce SEO and email marketing teams can help. Get a quote and tell us which products sell out most often.
Further reading on pre-orders and back-in-stock alerts
- Discount Strategy: Run Sales Without Training Customers to Wait
- Buy Now, Pay Later and Payment Options: Effect on Conversions
- Amazon A+ Content and Brand Stores: Lift Conversions on Amazon
Sources for this pre-orders and back-in-stock guide
- Google Search Central: Temporarily pause or disable a website
- Google Merchant Center Help: Product data specification
- Google Search Central: Merchant listing (Product, Offer) structured data
- Google Search Central: How to launch an ecommerce site on Google
- FTC: Advertising FAQs — A Guide for Small Business
- GOV.UK / CMA: New consumer protection regime comes into force (7 April 2025)
