Conversion rate: sessions, users and repeat orders
Define both numerator and denominator before comparing a conversion percentage.
Method
Conversion rate = qualifying conversions ÷ eligible opportunities × 100. Decide whether the opportunities are sessions, users, leads or clicks. Orders per session and the percentage of users who purchase measure different things. Repeat orders can make an order-per-user ratio exceed 100%; that does not mean more than all users converted.
Worked example
There are 2,000 sessions, 1,600 users, 60 orders and 50 distinct buyers. Orders per session = 60 ÷ 2,000 = 3%. Buyers per user = 50 ÷ 1,600 = 3.125%. Orders per user = 3.75%, but its numerator counts orders, not distinct buyers. Choose the matching numbers rather than interchanging them.
What to check
Match time window, eligibility and event definition. Do not compare a paid landing-page rate with an all-site user rate as though only the design changed. This calculator divides the values entered; it cannot deduplicate buyers or identify the correct population from a single total.