What counts as a sticky add-to-cart
A sticky add-to-cart is a bar or button that stays on screen as the shopper scrolls, so they never have to find the main buy box again. In this collection it shows up on product pages and on a listicle landing page.
The win/loss record
4 wins, 0 losses, 0 flat. That's a thin base. Three of the four results are Dave Diederen's, and one is part of a larger redesign, so treat this as a strong lead rather than a settled answer.
Where sticky add-to-cart was tested
- Product page: 3 tests
- Landing page (listicle): 1 test
Biggest wins and their numbers
Scroll back to the buy box, don't add to cart
Dave Diederen's sticky add-to-cart bar that scrolls back to the main buy box gained +11.67% conversion rate, +17.39% revenue per visitor and +5.12% AOV. Dave's view is that shoppers who scroll down are often still deciding, so sending them back to the variant and quantity options works better than dropping the product straight into the cart.
A second Dave test, a sticky bar that scrolls to the top when a variant or bundle must be picked, reported +$32,565/month. Dave's reasoning: tapping add to cart before choosing a size or bundle throws an error, which is friction.
When the sticky bar appears
On a listicle, Dave triggered the sticky CTA bar at the first in-page CTA (about 30% down the page) instead of only when readers scrolled back up. Result: +3.10% conversion rate and +2.88% revenue per visitor, AOV unchanged. Dave is clear that 30% isn't a magic number; the point is matching the bar to where the page first asks for action.
As part of a redesign
Oliver Kenyon's product page update added a sticky ATC alongside a rating under the title, a discount badge moved next to the ATC and clickable thumbnails. It reported +$38,846/month (+$466,152/year forecasted), but the sticky bar's share can't be separated out.
@oliverkenyon
@DaveDiederen@DaveDiederen@DaveDiederenTests that lost or were flat
None are recorded. That doesn't mean sticky bars never lose. With only four results, a missing loss tells you very little.
Design patterns worth copying
- Route to the buy box when choices are needed. Both of Dave's product page wins scroll the shopper up rather than adding a default variant.
- Show it early on long pages. The listicle test showed the bar from the first in-page CTA.
- Carry key info in the bar. Kasper Dolk's idea for a sticky ATC bar with reviews, price/discount and variant image is untested here but worth a variant.
Ideas not yet measured
Dave also suggests a sticky bar that adapts to variants. In the cart, Dave's idea to keep the checkout button sticky applies the same logic one step later.
How to add one on Shopify
Some themes include a sticky add-to-cart option in the theme settings; others need an app or custom code. Check whether the button adds to cart or scrolls to the buy box, because that behavior is what Dave's tests turned on.
How to test it on your store
- Hypothesis: keeping a path to the buy box visible at every scroll depth will lift revenue per visitor, most on long mobile pages.
- Metric: revenue per visitor, with conversion rate and AOV as checks.
- Variants: if you have traffic, test scroll-to-buy-box against direct add-to-cart.