Which has better ROI, SMS or email?
Neither channel wins outright — they earn ROI on different jobs. Email is nearly free per send and returns roughly $36 per $1 by Litmus's estimate (2021), making it the volume channel. SMS costs a few cents per message but gets opened almost immediately, so it wins on urgent, high-intent sends like cart recovery.
The honest version of this comparison starts with a definition. "ROI" gets used two different ways: program-level ROI (everything a channel earned divided by everything it cost, across a year of sends) and per-message ROI (what one specific send returned). Email's famous numbers are program-level, from surveys of marketers. SMS's best numbers are per-message, from individual campaigns — because each text costs real money, stores measure it send by send. Comparing a program-level survey average against a per-send campaign figure tells you nothing; comparing what each channel does well tells you everything. That's how the rest of this guide is organized.
The benchmarks, side by side
Here are the benchmark numbers worth trusting, with sources and dates. Where a reliable cross-industry figure exists we quote it approximately; where only vendor marketing numbers exist — SMS click-through and conversion — we say so and describe the pattern instead. Treat any precise-sounding SMS benchmark without a named source as sales copy.
| Metric | SMS | |
|---|---|---|
| Open rate | Roughly 20% — low twenties in Mailchimp and Campaign Monitor benchmark reports; opens spread over hours or days | Commonly cited around 98% (a figure often attributed to Gartner, 2016); most reads happen within minutes |
| Click-through rate | Around 2–3% of delivered emails (Mailchimp / Campaign Monitor benchmarks) | No trustworthy cross-industry benchmark — typically a multiple of email's, but published figures vary too widely by list quality to quote one |
| Conversion | Strongest on considered purchases and nurture sequences that build over multiple sends | Strongest on urgent, high-intent sends — abandoned carts, flash sales, back-in-stock |
| Cost per send | A fraction of a cent | A few cents per message; varies heavily by destination country |
| Typical ROI | Litmus (2021) puts it around $36 per $1 spent; the UK DMA's 2019 tracker found a similar order of magnitude | No Litmus-style cross-industry study exists — returns are best measured per send, and are highest on time-sensitive, high-intent messages |
Sources: Litmus State of Email survey (2021) for email ROI; Mailchimp and Campaign Monitor email benchmark reports for open and click rates; the ~98% SMS open figure is the industry number most often attributed to Gartner (2016). Where no reliable cross-industry study exists, we say so rather than quote a vendor number. Last reviewed July 2026.
Two caveats before you lean on any of these. First, email open rates have been partly fictional since Apple's Mail Privacy Protection shipped in 2021 — Apple Mail pre-fetches messages, registering "opens" nobody made, so treat open rate as a directional signal and judge email on clicks and orders instead. Second, most precise SMS statistics in circulation come from companies that sell SMS. That doesn't make the underlying pattern wrong — texts really are read faster and far more often than emails — but it should make you distrust any suspiciously exact decimal. Wherever possible, benchmark against your own sends, not the industry's.
Where email wins
Email wins on cost, depth, and scale. Sends cost a fraction of a cent, so large lists and frequent sends stay profitable. It carries long-form content — images, product grids, editorial — that a 160-character text can't. That makes it the right channel for newsletters, education, nurture sequences, and considered purchases.
The economics explain the famous ROI figures. When a send costs almost nothing, nearly any revenue it produces counts as return — which is how Litmus's 2021 survey lands around $36 back per $1 spent, and the UK DMA's 2019 tracker reported a comparable multiple. Email is also the channel where sophistication compounds: you can A/B test subject lines cheaply, build automated welcome and win-back flows, and segment deeply without each experiment costing money. And it's the only channel with room to actually sell — a product story, a comparison, a lookbook. If the purchase needs convincing rather than reminding, email does the convincing.
Email's weakness is attention. Your message lands in a crowded inbox, often filtered into a promotions tab, and gets opened — if at all — hours or days later. For a newsletter that's fine. For a "sale ends tonight" message, it's fatal.
Where SMS wins
SMS wins on attention and speed. Texts are opened at rates commonly cited around 98% (a figure usually attributed to Gartner, 2016), most within minutes — so a message about an expiring cart or a 24-hour sale actually lands in time to matter. It costs a few cents per send, which is why it's reserved for urgent, high-intent moments.
The phone's message inbox is the one place marketing barely reaches, and that scarcity is the whole advantage: a text interrupts, an email waits. That makes SMS the right channel whenever timing is the difference between a sale and nothing — an abandoned cart that goes cold within hours, a flash sale ending tonight, a back-in-stock alert for a product that will sell out again. The per-message price enforces its own discipline. At a few cents per send, blasting an irrelevant offer to your whole list costs real money and burns opt-outs; a targeted text to someone who just left a full cart is among the highest-return messages in e-commerce.
SMS ROI is also unusually easy to measure, precisely because it's priced per message: revenue attributed to the send, divided by what the send cost. Run your own numbers — list size, message cost, click and conversion assumptions — in our free SMS ROI calculator rather than trusting anyone's benchmark, ours included.
Using both together
The strongest programs sequence the two. Use email for nurture, newsletters, and education; use SMS for time-sensitive offers, order updates, and abandoned-cart recovery. A common recovery pattern: SMS first while intent is hot, email as the cheaper follow-up. Together they convert more shoppers than either channel alone.
The clearest example is cart recovery. Around 70% of online carts are abandoned (Baymard Institute's long-running average), and intent decays fast — the shopper who leaves a cart at noon has usually moved on by dinner. A text sent within the first hour reaches them while the purchase is still on their mind; an email a few hours or a day later catches the ones who prefer their inbox, at a fraction of the cost. The same sequencing logic works in reverse for promotions: announce a sale by email, where there's room for images and a full pitch, then send a short SMS in the final hours to the segment that clicked but didn't buy. Each channel covers the other's blind spot — email's slowness, SMS's brevity.
Tooling-wise, the split is the same as the strategy. CartBoss handles the automated, behavior-triggered leg — abandoned cart recovery and lifecycle texts that fire off a single shopper's actions, billed per message sent. For the one-to-many promotional leg — the flash-sale blasts and product-drop announcements — BuzzBlaster, from the same team, sends bulk campaigns to 30+ countries. Neither replaces your email platform; they cover the jobs email is too slow for.