Sticky Add to Cart on mobile product pages: +21.46% cart clicks
Commentary byLiftArchiveOur analysis, not theirsLocking the Add to Cart button to the bottom of the screen on mobile product pages raised click-through to cart by 21.46%.
U-Digital, a Dutch digital agency, ran this A/B test for a Dutch skin care ecommerce store, and it was published as a VWO case study.
The test measured clicks to the cart, not completed purchases.
- Mobile click-through to cart from product pages: +21.46%.
- About 7,200 visitors took part over roughly 23 days, split evenly between control and variant.
- Purchases and revenue were not reported, so the effect on sales is unknown.
The change
The Add to Cart button stays fixed at the bottom of the mobile screen.
Simplified mockup drawn by LiftArchive from the shared screenshots.
Control
On mobile product pages, the Add to Cart button sat in its normal place and scrolled out of view as shoppers moved down the page.
Variant
The Add to Cart button was fixed to the bottom of the screen, so it stayed visible while shoppers scrolled.
Why it likely won
Our reading of the result, not the practitioner's claim.
- Shoppers reading reviews or ingredients lower on the page could add the item without scrolling back up.
- A button that stays on screen is a constant, low-effort prompt to act.
- Skincare buyers often read a lot before deciding, so they spend more time away from the original button.
Caveats: The client is anonymized. The sample was modest at about 7,200 visitors over 23 days, and the metric was clicks to cart rather than orders.
Who ran it
U-Digital ran this test for a Dutch skin care ecommerce store and published the results (VWO case study). The numbers are theirs; the summary and commentary on this page are ours.
Read the original case study on U-Digital →
How to run this test on your store
- Hypothesis
- If we keep the Add to Cart button fixed at the bottom of the mobile screen, then more shoppers will click through to the cart because the button is always within reach.
- Primary metric
- Mobile click-through to cart from product pages
- Guardrails
- Mobile orders per visitor
- Cart abandonment rate
- Accidental add-to-cart removals
- Who should test it
- Stores with long mobile product pages where the buy button scrolls away early. It will likely do little if your product pages are short or already put the button near the bottom.
Questions
Does a sticky Add to Cart button increase sales?
In this test it raised clicks to the cart by 21.46%.
Sales were not reported, so check orders as well when you run your own test.
Should the sticky button be on desktop too?
This test was mobile only. Desktop screens show more of the page at once, so the gain is often smaller there.
How many visitors do I need for this test?
This one used about 7,200 visitors. Smaller lifts need more traffic, so use a sample size calculator before you start.
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