Conversion rate
The percentage of email recipients who completed the desired action (purchase, signup, reply, etc.).
Conversion rate in email is the percentage of recipients who completed the desired downstream action after receiving the email — typically a purchase, signup, reply, demo booking, or asset download. Calculated as (conversions / sends) × 100, or sometimes as (conversions / clicks) for funnel-stage analysis.
Conversion rates vary dramatically by email type and audience temperature. Newsletter sends might convert 0.1–0.5% to a purchase. Cart-abandonment emails convert 8–15% to recovery. Cold outreach measured by reply rate runs 5–20% in well-researched sequences. Cross-context comparison is meaningless.
The single biggest lift on conversion rate is audience relevance: the same email sent to 1,000 well-matched recipients will outperform the same email sent to 10,000 broadly-matched ones, in absolute conversions and almost always in revenue per send. List segmentation isn't a nice-to-have; it's the leverage.