One-measurement size finder: +33.1% conversion, not significant
Test run byClean CommitCRO agency
Commentary byLiftArchiveOur analysis, not theirsSwapping a long 'Find Your Size' tool for a single-measurement size finder raised conversion rate by 33.1% and revenue per visitor by 14.9%, but the result was not statistically significant.
Clean Commit ran this test for an anonymized Shopify store and published it in its A/B test library. We count it as inconclusive.
- Conversion rate: +33.1%. Large, but not statistically significant.
- Orders: +32.3%, in line with the conversion gain.
- Revenue per visitor (the goal metric): +14.9%, with a 72.5% probability of beating the original. That is a weak signal.
- Add-to-cart rate: +8.3%.
- Average order value: -14.6%. This negative move ate much of the revenue gain.
The change
A one-input size finder replaces long instructions and pre-selects the size.
Simplified mockup drawn by LiftArchive from the shared screenshots.
Control
The product page had a 'Find Your Size' tool with long instructions for shoppers to read before getting a size.
Variant
A short size finder took one measurement in inches or centimeters, showed the matching size straight away and pre-selected it in the size picker above which it sat. The same finder was added to Buy Now sections across the site.
Why it likely came out this way
Our reading of the result, not the practitioner's claim.
- One input and an instant answer removes the reading and guesswork that make shoppers unsure about size.
- Pre-selecting the size cuts a step between finding a size and adding to cart.
- The drop in order value may mean more shoppers bought a single item once sizing felt settled, rather than ordering extra sizes.
- With 20,402 visitors and a 72.5% probability, the lift could still be noise.
Caveats: 20,402 visitors over 21 days, and the goal metric did not reach significance. Average order value fell 14.6%, so revenue gained far less than conversion rate.
Who ran it
Clean Commit ran this test for a Shopify store (anonymized) and published the results (Clean Commit A/B test library). The numbers are theirs; the summary and commentary on this page are ours.
Read the original case study on Clean Commit →
How to run this test on your store
- Hypothesis
- If we replace long sizing instructions with a single-measurement finder that pre-selects the size, then revenue per visitor will rise because shoppers settle sizing doubts faster.
- Primary metric
- Revenue per visitor
- Guardrails
- Average order value
- Return rate for wrong size
- Add-to-cart rate
- Who should test it
- Apparel, footwear or gear stores where size is a common reason to hesitate. It matters less if your products fit most people or if size can be guessed from one simple choice.
Questions
Does a size finder increase conversions?
In this test a simpler finder lifted conversion rate 33.1%, but the result was not significant and order value fell.
Treat it as a promising idea to test on your own store.
Should a size finder pre-select the size?
Pre-selecting saves a click and confirms the answer.
Watch returns, since a wrong recommendation now costs you more.
Why did average order value drop?
The source does not say. One possible reason is that shoppers who trust the recommended size order one item instead of several sizes.
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