Sticky add-to-cart bar on product page: +11.30% revenue per visitor
Test run byDave DiederenSyntra Labs
Commentary byLiftArchiveOur analysis, not theirsAdding a sticky add-to-cart bar to the product page raised revenue per visitor by 11.30% and conversion rate by 14.16%. Dave Diederen calls it their most consistent winner and estimates about A$32,565 a month from this test. For products with variants or bundles, they suggest the bar scrolls shoppers back up to choose first instead of adding straight to cart.
- Revenue per visitor (primary metric): A$5.11 to A$5.69, +11.30%, an estimated A$32,565 a month.
- Conversion rate: 4.96% to 5.66%, a 14.16% relative lift.
- Average order value fell 2.51% (A$103.04 to A$100.45). More people bought, but slightly smaller orders.
- A third version, a sticky bar with a different setup (its label is cut off), reached 5.45% conversion and A$5.44 per visitor. That beat control but not the main variant.
- A separate test on another store tried a text-style 'Add To Cart' version. It showed a smaller lift: +2.57% conversion, +2.72% revenue per visitor, and no change in order value.
The change
A fixed add-to-cart bar follows the shopper down the page.
Simplified mockup drawn by LiftArchive from the shared screenshots.
Control
The product page had a single add-to-cart button near the top. Shoppers who scrolled into reviews had to scroll back up to buy.
Variant
A bar with the add-to-cart button stayed fixed on screen as shoppers scrolled. When a size or bundle must be picked first, tapping it scrolls to the selector instead of adding to cart.
Why it likely won
Our reading of the result, not the practitioner's claim.
- long product pages push the buy button off screen. Keeping it visible removes the scroll back up.
- this matters most on mobile, where reviews and details take up many screens.
- sending shoppers to the variant picker avoids the error you get from adding to cart before choosing a size.
Caveats: Confidence ranges were wide (-9% to +44% on conversion, -20% to +55% on revenue per visitor). The test dates and sample size were not shared. The example stores in the post's images are illustrations, not necessarily the test site.
Who ran it
Dave Diederen (@DaveDiederen) shared this test on X. The numbers and screenshots are theirs.
View the original post on X
How to run this test on your store
- Hypothesis
- If we keep an add-to-cart bar fixed on screen as shoppers scroll, then more will buy because they can act at any scroll depth without scrolling back up.
- Primary metric
- Revenue per visitor
- Guardrails
- Average order value
- Add-to-cart error rate
- Bundle or multi-unit take rate
- Who should test it
- Stores with long, mobile-heavy product pages full of reviews and content. Short pages where the main button stays in view will gain less.
Questions
Does a sticky add-to-cart button increase conversions?
In this test it lifted conversion 14.16% and revenue per visitor 11.30%. Average order value dipped 2.51%, so watch basket size too.
What should a sticky add-to-cart do if the product has sizes?
Dave Diederen suggests scrolling the shopper up to the size or bundle picker instead of adding to cart. That avoids an error from adding before a choice is made.
Is a sticky add-to-cart bar worth it on desktop?
They note the lift grows with page length, especially on mobile. Desktop results were not broken out in this test.
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