SMS Marketing vs Email: Open Rates, Revenue, and When to Use Each

SMS marketing gets a 98% open rate. That number sounds like a marketer's dream, and brands use it to justify aggressive SMS programs. But revenue per message sent tells a different story — email consistently outperforms SMS on revenue generation. Understanding why, and how to use both channels together, is the difference between a high-performing retention program and an over-texted, unsubscribing list.

Side-by-Side Comparison

Why Email Still Wins on Revenue

SMS has a higher open rate because texts feel urgent — people open them reflexively. But that urgency cuts both ways. A marketing text that interrupts someone at the wrong moment gets deleted instantly or triggers an unsubscribe. Email allows nuance, storytelling, multiple CTAs, product imagery, and personalization at scale. That content depth is what drives revenue.

According to Klaviyo's SMS marketing data, email revenue attribution typically runs 3–5x higher than SMS per message delivered for brands running both channels. The gap closes during flash sales and time-sensitive promotions, where SMS's immediacy makes it the superior channel.

When to Use SMS vs Email

How to Run Both Without Burning Your List

The brands that get SMS wrong do one of two things: they text too frequently (3–4 times per week) or they send the same promotional content they already sent via email. SMS should feel different from email — more direct, more exclusive, more urgent. If your SMS subscriber could get the same message via email, you're not using the channel correctly.

In Klaviyo, you can build SMS and email into the same flows with channel-specific logic. An abandoned cart flow, for example, can send an email at hour 1, then an SMS at hour 4 if no purchase, then a final email at 24 hours. Each touchpoint adds pressure without feeling redundant because the message and medium are different.

For the email side of this equation, read our guide on the 5 Klaviyo flows every ecommerce brand must have.

The Compliance Non-Negotiable

SMS marketing in the US is regulated by the TCPA (Telephone Consumer Protection Act). You must have explicit written consent before sending marketing texts — pre-checked opt-in boxes don't count. Every SMS must include easy opt-out language (STOP to unsubscribe). Klaviyo's SMS tools are built with TCPA compliance in mind, but the obligation to get proper consent is on you, not the platform.