What is conversion rate? Definition and formula

Conversion rate is the share of visitors or sessions that complete a goal you care about, such as a demo request, sign-up or purchase, over a set period.

How it works

The formula is simple:

conversion rate = conversions ÷ visitors (or sessions) × 100

Optimizely's glossary gives a worked example: a page with 2,000 visitors a month and a 10% conversion rate produces 200 conversions; raising the rate to 15% produces 300 (Optimizely).

The hard part is deciding what goes on each side of the division:

• The goal. A purchase, a booked demo, a trial sign-up, a newsletter subscription. Track a few business goals separately rather than one blended number.
• The denominator. Users, sessions or page views give different rates for the same traffic. Pick one and keep it.
• The period and segment. A site-wide rate hides the difference between a pricing page and a blog post, or between paid and organic traffic.

Analytics tools have their own vocabulary. In Google Analytics 4, an action that matters to your business is called a key event, and "conversion" is now reserved for the measurement of ad campaigns in a linked Google Ads account; Google summarizes the chain as "Event → Key Event → Conversion" (Google Analytics Help).

Why it matters for your website

Conversion rate is the number that connects traffic to revenue, which makes it the usual yardstick for any change to a site, including adding an AI assistant. Two cautions:

• Count outcomes, not activity. "Chats started" is easy to inflate. "Chats that ended in a booked meeting or a qualified lead" tells you whether the assistant helps.
• Expect fewer, different visits. When AI search answers simple questions on the results page, some visitors never arrive (see zero-click search). Watch conversions per visit and absolute conversions together, so a falling traffic number isn't mistaken for a falling site.

Avoid comparing your rate with generic industry benchmarks; goals, traffic mix and definitions differ too much for the comparison to mean much. Your own trend is the useful baseline.

Example

A B2B site tracks one key event, demo_booked (illustrative numbers):

Sessions fell slightly while demos rose, so the rate went up. To credit the chat, compare demos booked through the chat against the same period's form bookings, and run the comparison long enough to rule out seasonality.

Related terms

• Conversion rate optimization (CRO): the practice of raising this number.
• Lead qualification: which conversions are worth counting.
• Search intent: why some pages convert better than others.
• Zero-click search: why traffic can fall while outcomes hold.