# Sticky footer add-to-cart on mobile: +10% clicks, +9% conversion

- Outcome: Won
- Page type: Landing page (Ecommerce)
- Elements: Sticky add-to-cart bars
- Test run by: [Ezra Firestone](https://liftarchive.com/practitioners/ezra-firestone/)
- Commentary by: LiftArchive (our analysis, not theirs)
- Original source: https://zipify.com/mobile-sticky-button-split-test-results/
- Page: https://liftarchive.com/test/gap-zipify-sticky-footer-atc-mobile/

Adding a sticky add-to-cart button to the bottom of a mobile sales page lifted add-to-cart clicks by 10% and order conversion by 9%, at 95% confidence. Ezra Firestone ran the test on an 8-figure Shopify store the founder owns and published it on the Zipify blog. A second run gave a similar result.

## Result

**+10% clicks, +9% conversion**

- Add-to-cart clicks on mobile: +10% vs the original page.
- Order conversion rate: +9%, at 95% confidence.
- Retest: +$1.70 average order value, +$0.46 per session value and a higher conversion rate.
- The sticky-header variant's numbers were not shared. Visitor counts were not given.

## Control

The mobile sales page had its add-to-cart button only below the buy box. Once shoppers scrolled past, the button was gone.

## Variant

A sticky add-to-cart button stayed fixed at the bottom of the screen while shoppers scrolled. A sticky-header version was also tested, but its result was not shared.

## Why it likely won (our reading)

- On a long mobile page, the buy button scrolls out of view. A sticky button keeps it in reach.
- The bottom of the screen is where thumbs naturally rest, which makes it easy to tap.
- Shoppers who decide mid-page don't have to scroll back to buy.

## Caveats

Published by Zipify to promote its own sticky-button feature, on the founder's own store. Sample size was not shared and the sticky-header result was left out.

## How to run this test

- Hypothesis: If we add a sticky add-to-cart button at the bottom of the mobile screen, then order conversion will rise because the buy action stays in reach as shoppers scroll.
- Primary metric: Mobile order conversion rate
- Guardrail: Mobile add-to-cart rate
- Guardrail: Average order value
- Guardrail: Bounce rate
- Who should test it: Stores with long mobile product or sales pages where the buy button scrolls away. Short pages with the button always visible will see little change.

---

Credit: Ezra Firestone ran this test and owns the result. Summary and commentary by LiftArchive (https://liftarchive.com/test/gap-zipify-sticky-footer-atc-mobile/).
Usage: Free to use, quote and build on, with credit and a link: name the practitioner or organization that ran the test and link to its LiftArchive page. The results belong to the practitioners who ran and shared them; the summaries and commentary are LiftArchive's.