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Cart & Checkout

CTA Button Color A/B Test Example on the Cart Page

Changing the CTA color may affect clicks by changing how clearly the button stands out against its surroundings.

  • Cart
  • Click-through rate (CTR)

Control vs Variant

The visual treatment is the variable, not the words or the position.

Changed
Visual style
Page
Cart
Difference
changed

Hypothesis

Keep its wording, size, position and surrounding design the same.

How to run this test

Primary metric

Click-through rate (CTR)

Compare clicks on the cart CTA between visitors assigned to each color.

Other metrics

  • Purchase conversion rate (CR)Compare completed orders among all visitors assigned to each experience.
  • Checkout start rateCompare assigned cart visitors who proceed to checkout.
  • Cart page exit rateCompare the share of assigned visitors who leave the cart page.

What to check before and during the test

  • ColorCompare the current CTA color with one preselected, brand-approved alternative. Record both color values before launch.
  • ContrastKeep the label easy to read and maintain accessible contrast in both versions.
  • Keep constantDo not change the button label, size, position or surrounding design.
  • TrackingVerify CTA impressions and clicks, checkout starts and completed orders are attributed to the correct variant.
  • DeviceReview mobile and desktop separately.

Setup mistakes to avoid

  1. 1Change only the CTA color.
  2. 2Use only colors approved for the brand and check text contrast in both versions.
  3. 3Keep the button label, size and position the same.
  4. 4Do not call a winner from clicks alone; review completed orders too.
  5. 5Validate the result in the page context where the test ran before applying it elsewhere.