Conversion Rate
Conversion rate is the percentage of an eligible audience or set of visits that completes a defined action.
What is Conversion Rate?
In ecommerce, the action is usually a purchase, but conversion can also mean a signup or another event. A usable conversion rate names both the action and the denominator. “Purchase conversion per session” is more precise than an unlabeled percentage.
For an online store, a session is a visit rather than a unique person. One shopper may return several times before buying. Session-based and customer-based conversion rates therefore describe different things and can both be correct.
Session purchase conversion rate (%) = Sessions with a purchase ÷ Eligible sessions × 100
Count a converted session once even if it contains more than one order. An orders-per-session calculation is a different measure. Use the same reporting window and channel scope.
250 purchasing sessions out of 10,000
A store records 10,000 eligible online sessions, of which 250 include a purchase. Session purchase conversion is 2.5%. If five of those sessions contain a second order, total orders are 255, but converted sessions remain 250 and the session conversion rate remains 2.5%.
How to interpret it
The rate describes how often eligible visits completed the action. It is influenced by traffic intent, device, product availability and checkout experience. A lower rate after expanding into a new audience is not automatically evidence that the site became harder to use.
Read conversion alongside traffic volume, AOV and contribution per order. A promotion might increase the purchase rate while reducing profit on each basket. Conversely, excluding low-intent traffic can raise the rate without creating additional sales.
The numerator and denominator depend on measurement. Consent choices, tracking gaps, bot filtering and session definitions can affect reported values. Compare the same analytics source and configuration where possible, and investigate discontinuities after tracking changes.
Shopify defines its online store conversion measure around sessions that result in a sale. Do not combine all-channel orders with online-store-only sessions: point-of-sale or other channel orders would inflate a denominator that never included their audience.
Common mistakes
Treating visits as unique shoppers
Repeated visits from one person count as multiple sessions. A visitor-based conversion figure needs its own identity and measurement rule.
Judging a small sample as a stable rate
Two purchases from 40 sessions produce 5%, but that estimate is much more sensitive to a single extra order than the same percentage across a large sample.
Definition reference: Shopify analytics field definitions.