Definition
CRO (Conversion Rate Optimization)
CRO is the systematic process of testing and improving a website or funnel to increase the percentage of visitors who take a desired action.
CRO relies on structured hypothesis testing — reviewing analytics and session recordings, forming a specific hypothesis about what’s causing friction, then running an A/B test to validate it — rather than redesigning a page based on personal taste. Because CRO improves the conversion rate of existing traffic, gains compound across every other channel feeding that page, making it one of the highest-leverage investments once a site has meaningful traffic volume.
CRO in practice
An online store notices that many mobile shoppers leave on the delivery page. The team's hypothesis is that surprise delivery charges cause it, so they test showing delivery costs on the product page instead. If the version with upfront costs gets more completed orders over a full test period, it becomes the new default.
Related terms
Common questions about CRO
What is a good conversion rate?
It varies widely by industry, traffic source and offer. Rather than chasing a benchmark, measure your own baseline and improve on it with tested changes.
What should I test first?
Start where traffic and drop-off are highest: the headline and offer, the call to action, form length, page speed and trust signals such as reviews and guarantees.
How long should an A/B test run?
Until each version has enough conversions for a reliable result, and for at least one to two full weeks to cover weekday and weekend behaviour. Stopping early often picks the wrong winner.
Do you need a lot of traffic for CRO?
For reliable A/B tests, yes. With low traffic, it's usually better to fix clear problems found through analytics, session recordings and customer feedback than to wait months for a test to reach a result.
