Sticky add-to-cart bar that scrolls to the buy box: +17.39% RPV
Test run byDave DiederenSyntra Labs
Commentary byLiftArchiveOur analysis, not theirsAdding a sticky add-to-cart bar that scrolls shoppers back up to the main buy box lifted revenue per visitor by 17.39% in Dave Diederen's test. Conversion rate rose 11.67% and average order value rose 5.12%. A third version in the same test did worse than the control.
- Revenue per visitor: +17.39% ($2.79 to $3.27). The range was very wide (-51% to +182%), so the true lift is uncertain.
- Conversion rate: +11.67% (1.35% to 1.51%). More visitors ordered, though the range (-39% to +103%) includes a loss.
- Average order value: +5.12% ($206.70 to $217.29). Orders were a little bigger too.
- Third version: a second sticky bar variant, its label cut off in the screenshot, fell to 1.14% conversion and $2.10 per visitor, below control. The post implies this was the add-straight-to-cart version, but it is not labelled.
The change
A sticky bar appears on scroll and takes shoppers back to the main buy box.
Simplified mockup drawn by LiftArchive from the shared screenshots.
Control
The product page had no sticky bar. Once shoppers scrolled past the buy box, there was no add-to-cart button in view.
Variant
A sticky add-to-cart bar stayed on screen while scrolling. Tapping it took the shopper back up to the main buy box rather than adding the product to the cart straight away.
Why it likely won
Our reading of the result, not the practitioner's claim.
- many shoppers who scroll down are still deciding, and sending them back to the buy box lets them check options and key points first.
- a button that adds to cart instantly can skip the size or variant choice and push people before they are ready.
- keeping a buy button in view still cuts the effort of scrolling back up for people who have decided.
Caveats: Sample size and test length were not shared, and conversion was low (about 1.4%), so the ranges are very wide. Only one store's result was shown, though Dave Diederen says sticky bars have won for them across several verticals.
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 add a sticky add-to-cart bar that scrolls shoppers back to the main buy box, then more of them will buy because a buy button is always in reach without skipping variant choice.
- Primary metric
- Revenue per visitor
- Guardrails
- Average order value
- Cart abandonment rate
- Return rate for wrong size or variant
- Who should test it
- Stores with long product pages and products that need a variant, size or quantity choice. It may add less on short pages where the buy box is always close.
Questions
Does a sticky add-to-cart button increase conversions?
In this test it did. A sticky bar that scrolled back to the buy box lifted conversion rate by 11.67% and revenue per visitor by 17.39%.
Should a sticky ATC add to cart directly or scroll to the buy box?
Dave Diederen says the scroll-to-buy-box version wins for them. In this test, a second sticky version did worse than having no bar, though its exact setup is not labelled.
Does a sticky add-to-cart bar affect order value?
Here, average order value rose 5.12%, from $206.70 to $217.29.
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