Handling Out-of-Stock Sizes on Shopify (Without Losing the Sale)
A sold-out size is a customer who was ready to buy. Greying out the button and letting them leave is the default — and it's the most expensive option available.
Quick answers
- What's the worst option?
- Greying out the size and doing nothing else
- Cheapest win?
- A back-in-stock email alert
- Should I push an adjacent size?
- Only if the fit genuinely allows it
- Why does this matter?
- A sold-out size is a ready-to-buy customer
Options When a Size Is Out
| Option | Outcome |
|---|---|
| Grey out the variant | Customer leaves |
| Back-in-stock alert | Capture the email, recover later |
| Suggest adjacent size | Risky — only if fit allows |
| Pre-order the size | Capture the sale now |
| Recommend similar product | Keeps them on site |
Notes
Always capture the email. A back-in-stock alert costs nothing and converts unusually well, because the person asking for it has already decided they want the item. It's the single highest-intent email address you can collect.
Be careful pushing an adjacent size. Suggesting an L to someone who wanted an M is a fast route to a return. Only do it where the garment's fit is genuinely forgiving (relaxed knitwear, elastic waists) and say so honestly: "this style runs roomy, an L may still work for you."
Pre-order beats losing the sale. If the size is on reorder, let them buy it now with a clear ship date. You capture the revenue, and you also get a real demand signal for your next size curve — which is exactly the data that stops the stock-out recurring.
Stock-outs distort your data — flag them. Every day a size is unavailable, its recorded demand is artificially zero. If you don't track availability, your next buy will under-order the size that sells best. Note it, or the problem repeats forever.
FAQs
What should I do when a size sells out on Shopify?
At minimum, offer a back-in-stock email alert — the customer has already decided they want it, so it's the highest-intent email you can collect. Better still, offer the size as a pre-order with a clear ship date so you capture the sale now.
Should I suggest a different size when one is out of stock?
Only if the garment's fit genuinely allows it — relaxed styles, knitwear, or elastic waists. Pushing an adjacent size on a fitted garment just converts a lost sale into a return. If you do suggest it, be honest about how the style runs.
How do out-of-stock sizes affect my inventory planning?
They understate demand. A size that was unavailable for half the season shows artificially low sales, so planning your next buy from raw units sold will make you under-order it again. Always adjust for how long each size was actually in stock.
Need this on your store?
Tailor Size Guide ships pre-built size charts for Shopify.