Don't hide your sold-out variants - they're doing work

When a size or colour sells out, most stores hide it. Tidies up the page, avoids frustration. The logic makes sense. But the data disagrees.

Research found that keeping sold-out variants visible - clearly marked as unavailable - increases sales by up to 31% among customers who haven't already decided exactly what they want.

Why sold-out options persuade

A sold-out option says: someone already wanted this enough to buy it. It's the highest-quality social proof on your page - proof of actual purchase, not just a review.

When a potential buyer sees "XS - Sold Out" next to "S - Available", they now know that your XS customers were enthusiastic enough to clean out the stock. That enthusiasm is contagious.

The ceiling you have to respect

The effect flips when too many options are unavailable. If buyers feel they can't freely choose, they feel controlled - and they leave. The research points to a threshold of 10-30%. If more than 30% of your variants are sold out, hide the least popular ones and keep the rest.

The practical version

On a 6-colour product where 2 are sold out: keep both sold-out colour swatches visible with a strikethrough or "Sold Out" label. Don't grey them out completely - they need to be readable.

On a 10-size shoe where 7 sizes are gone: show 3 sold-out sizes maximum. Hide the other 4.

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Research: Tian, J., Chen, R. & Xu, X. (2021). International Journal of Research in Marketing, 38(2). Tsinghua University, Hainan University & Agricultural Bank of China.