What’s up, guys?

Today, I want to talk about how we increased our add-to-cart conversion rate by 14.5% for our sustainable fashion apparel brand and got them +2600 Euro monthly. Our client has a marketplace working primarily in Europe and selling different clothes and accessories for people who care about the world, as all the products are economically, environmentally, and socially sustainable.

We were able to grow conversion by implementing a new UI feature that allows users to choose their size on the product page. Previously, users had to click through to the product details page in order to select their size, which was a major barrier to conversion.

Here’s how it works:


Test buttons for sizes versus a drop-down menu. This will increase the Add-to-cart conversion rate and as a result, may increase sales CR and revenue per user. It is always a good idea to find new ways to work with user experience, even with such small changes, such as choosing the size. It can seem like something not really impactful, but you will see in the results, that such changes can bring good results and do not require some complicated processes.

Conversion event:

Add-to-cart click.

We also monitored the eCommerce conversion rate and RPU per variation to see the effect on sales.

Test setup:

A/B test in Google Optimize with two variations: Original – with original drop-down size filter and Variation 1 – with modified buttons size filter. Modifications included layout, design, and usability.


What we have learned from this test:

This test has a positive effect on both micro conversions and macro conversions.

On a micro level, the new design of the size selector caused the uplift in the Add-to-cart conversion rate by +14.53%.

This result is statistically significant, with P-value (z-test) <0.004.

Although the CR uplift is not looking that high, its significance for the client testing program is huge.

  • The UI/UX category of tests has a significant effect on visitors’ behavior even when changes are very subtle. We can run more tests on this category with confidence.
  • If we do a line of tests on UI/UX on product pages, we can successfully solve one of the main problems in the current purchase funnel – the low CR of product pages.
  • Users get more confidence when they select the right product with confidence. This confidence in turn brings more revenue for our client.

The effect of the test on micro conversions is positive. The uplift in Ecommerce CR is +2.2% and on AOV it is +6%.