Email marketing is still the highest-ROI digital marketing channel by most measures. The average ROI cited in industry studies is between 35× and 42× — meaning 35 to 42 returned for every 1 spent.
The businesses that don't see this return are usually making one of three mistakes.
Mistake 1: Sending to the entire list every time
Segmentation is the single biggest lever in email marketing. A customer who bought once two years ago should not receive the same email as a customer who bought last week.
Segment by: recency of purchase, product category interest, stage in the funnel, and engagement level.
Mistake 2: Optimising for opens, not revenue
Open rate is a vanity metric. A 40% open rate with 0.1% click-to-purchase is worse than a 15% open rate with 2% click-to-purchase.
Optimise your email marketing for revenue per email sent.
Mistake 3: No automated sequences
The highest-value emails are automated: welcome sequences, abandoned cart, post-purchase, win-back. These are set up once and run indefinitely.
A good welcome sequence alone typically generates 20–30% of total email revenue.
What works in 2026
Plain-text emails from a named person outperform designed newsletters for most B2B use cases. Personalisation beyond first name — product recommendations, location, purchase history — dramatically improves conversion. And mobile optimisation is non-negotiable: over 70% of email is read on mobile.