Nearly every text gets read within minutes; most email never gets opened at all. So why do the best sales teams still send more email than SMS — and win with both?
| Metric | SMS | |
|---|---|---|
| Open rate | ~98% | ~20% |
| Response rate | ~45% | ~6% |
| Time to be read | Minutes | Hours to days, if at all |
| Length | 160 characters per segment | Unlimited, with attachments |
| Cost per message | $0.01–0.05 | $0.001–0.01 |
| Consent to market | Prior express written consent (TCPA) | None required for B2B first contact |
| Opt-out handling | STOP, honored immediately | Within 10 business days (CAN-SPAM) |
| Delivery gate | A2P 10DLC registration | Sender reputation, SPF/DKIM |
Open and response rates are the industry benchmarks that trace to Gartner, Mobilesquared, and Campaign Monitor — republished widely, so treat them as directional, not gospel; costs are typical US carrier and platform pricing. Your own by-channel reply data beats every benchmark here.
The table looks like a knockout for SMS — a 45% response rate is seven or eight emails’ worth of replies from a single text. But each number cuts both ways: the open and response rates exist because texting is scarce and personal, an inbox of five instead of a hundred. Spend that scarcity on a pushy pitch and you don’t get ignored like email; you get opted out, and under TCPA that door closes for good.
Email’s 20% sounds bleak until you notice what it buys: no consent barrier for a first B2B touch, unlimited room for a proposal, and a message the champion can forward to their boss with “thoughts?” Nobody forwards your text to the CFO.
One mechanical detail that surprises teams: the 160-character segment limit uses the basic GSM character set. Add a single emoji or curly quote and the message re-encodes, dropping each segment to 70 characters — so a “short” text quietly bills as three. Write SMS in plain characters and keep it to one segment.
Short, time-boxed, already-warm. Those three conditions describe the messages that should be texts:
A purchased list has no consent that transfers to you. Under TCPA, automated marketing texts without prior express written consent run $500–1,500 in statutory damages per message — and carriers filter the traffic anyway.
Anything that takes three segments to say belongs in an email the buyer can read on their terms and forward internally.
Three pushy emails get ignored; three pushy texts get you blocked and reported. The channel’s intimacy is the asset — treat it like a colleague’s number, not a list entry.
Unregistered business SMS is filtered or blocked outright before it ever reaches a phone — the whole 98% advantage evaporates. See how A2P 10DLC registration and throttling work.
Run the table’s own numbers and the ROI story flips from the one you expect. At a typical $0.03 per SMS and the cited ~45% response rate, a text reply costs about $0.07. At $0.005 per email and ~6% response, an email reply costs about $0.08. Per reply, the channels are nearly tied — what SMS buys isn’t cheaper conversation, it’s faster conversation with a lead who’s already warm.
Volume is where they separate. Ten thousand touches runs roughly $10–100 on email and $100–500 on SMS, before 10DLC campaign fees — so nurture and education ride the cheap channel, and SMS spends its budget on the moments where a same-hour answer changes the outcome: the confirmation that prevents a no-show, the question answered while the buyer is still on your pricing page.
Before any follow-up, ask: Is it short and time-boxed? If the message needs scrolling or thinking time, it’s email. Do I have their permission to text? If not, it’s email — or it’s the ask that earns the permission. Two yeses, and it’s a text. Everything else in this guide is elaboration on those two questions.
The pivot is the permission ask, and it lives at the end of a good call, not in a cold text:
From there, route by message: email when it needs detail or a forward, SMS when it needs an answer today. Full timing for the touches is in the follow-up cadence guide.
The channels live under different laws, and the SMS side is the strict one. Marketing texts need prior express written consent, STOP honored immediately, and sends kept to 8 AM–9 PM in the recipient’s time zone; email under CAN-SPAM needs honest headers, a physical address, and opt-outs honored within 10 business days. The details — and the state laws that go further — are in the TCPA compliance guide and the state-by-state rules.
FollowUp runs both channels in one sequence — email and SMS routed by message type, consent tracked, quiet hours enforced — and its AI reads every reply so only the ones needing a human reach you. Start with email, earn the text, and let the system keep both working.