Email vs SMS marketing: which message goes on which channel

You have an email list you have built over years and a growing pile of mobile numbers from checkouts and sign-up forms, and a sale starts Friday. The email vs SMS marketing question is answered one message at a time. Some messages belong in a text, most belong in an email, and a few belong in both, in a particular order.

Every page that ranks for this comparison is written by a company that sells one of the two channels, and it reads that way. This one sells neither. It gives you a sorting rule, eight worked examples, what each channel costs on the same list, and the consent rules for both, as they are published.

Email vs SMS marketing: the short answer

A message goes by text when all three of these are true: it has to be read within the hour, it fits in a sentence, and the person typed their mobile number in and ticked a box that said you would text them. Fail any one and it is an email.

That rule sounds strict because texts are expensive, in money and in attention. A text lands on the lock screen. That is why a "sale ends at midnight" text works and why a fourth text that week gets a STOP reply.

The 160-character figure is the GSM 7-bit alphabet's limit for one SMS segment. If a message contains a character outside that alphabet (an emoji, a curly quote, some accented letters) the whole message drops to 70 characters per segment. The limit comes from the standard itself, 3GPP TS 23.040, so no vendor can raise it.

The 98% open rate, and why it decides nothing

Half the ranking pages say texts have a 98% open rate and emails about 20%. We went looking for the study behind the 98% and did not find one; it is quoted from page to page with no primary source. There is a bigger reason to leave it out: nobody can measure an SMS open. A carrier returns a delivery receipt when the handset receives the message. Whether the person read it, or swiped the notification away, is not recorded anywhere. Any SMS open rate is a guess dressed as a number.

Email opens are measured, but badly. Since iOS 15 in September 2021, Apple's Mail Privacy Protection loads a message's remote images whether or not the person opens it, so the tracking pixel fires for readers and non-readers alike. An email open rate now overstates reading by an unknown amount that depends on how many of your subscribers use Apple Mail.

So the comparison the pages make, 98% against 20%, sets an unmeasurable number against an inflated one. Compare the two channels on what both can measure:

• Clicks per 1,000 messages sent, on a tracked link.

• Replies, where a reply is the action you want.

• Unsubscribes and STOP replies per 1,000 sent. This is the cost side of the same coin, and a text campaign that sells well and loses 2% of the list each time is not working.

• Revenue or bookings per send, when your platform ties the sale to the message.

Reach is not a difference either. The Pew Research Center's mobile fact sheet (survey of February to June 2025, published 20 November 2025) puts US cellphone ownership at 98% of adults and smartphone ownership at 91%. The channels differ in how fast the message is seen and how much it can say, not in who it can reach.

Which message goes on which channel: eight worked examples

Apply the three-part rule (needed within the hour, fits in a sentence, texting consent given) to the messages a small business actually sends.

Two messages go by text, four by email, and two by both, with the email carrying the record. The rule, not the channel, decides.

1. Sale ends at midnight. Text, sent that morning to the subscribers who opted in to texts. An email two days earlier carried the details; the text carries the deadline and one link.

2. Appointment tomorrow at 10. Text. It is needed on the day, it fits in a sentence, and a reply of "C" to confirm is worth more than any email.

3. Your order has shipped. Text for the moment, email for the record. The text says it has left; the email holds the tracking number, the invoice and the returns policy, which the customer will search for next week.

4. The monthly newsletter. Email. It fails all three tests: nothing in it is needed within the hour, it is three stories long, and a newsletter by text would burn the list in a month.

5. A new product, with photos. Email. Texts cannot carry a layout, and an MMS with one picture costs several times a plain text. Send a text only if there is a launch-day window ("first 50 orders ship free, today") and only to people who asked for texts.

6. Abandoned cart. Email at one hour, with the items and their pictures. A single text at 24 hours to opted-in subscribers, if the email got no click. Never the text first: the email can show what was left behind, the text can only say that something was.

7. A change to your prices or terms. Email. It is the written record the customer will want to find again, and it needs more than a sentence.

8. "How did we do?" Email when you want them to write something; text only when the whole answer is a number ("reply 1 to 5"). A text with a link to a five-page survey is a text nobody finishes.

Notice that the texts on this list are all things the reader would want to be interrupted for. That is the test of the third rule: consent covers the channel, but the message still has to earn the interruption.

What each channel costs on the same list

Email is priced by the size of the list, usually a monthly fee with unlimited or generously capped sends, so the second email you send in a month costs nothing extra. SMS is priced per message segment, with a monthly charge for the sending number on top. A two-segment text costs twice a one-segment text, which is why the 160-character limit belongs in the budget.

For one 5,000-contact list, four texts cost six to twelve times four emails in this example. A text is for the one message that needs it.

A worked example, with round numbers that are illustrative rather than any vendor's price list. Take a list of 5,000 contacts and a plan to reach them four times in a month.

• Email only. A plan for 5,000 contacts at $50 a month, four sends included. Cost per contact reached: 1 cent for the month, a quarter of a cent per message.

• SMS only. At 1.5 cents per segment, four one-segment texts to 5,000 numbers is 20,000 segments, $300. Write each text at two segments and it is $600. Add the number rental and the registration fees.

• Email plus one text. Four emails at $50, one one-segment text to the 5,000 for $75: $125, and the text goes only to the message that needs it.

The numbers will differ on your platform; the shape will not. Check the price per segment and the number fee on the pricing page of any SMS marketing software you consider, and the price band for your list size on any email marketing software. If a text costs six to twelve times an email per message, as it does in this example, it has to do six to twelve times the work. A deadline reminder can. A newsletter cannot.

Is email marketing worth it, then, if opens are unreliable and texts are quicker? Yes, on cost alone: it is the only channel where the marginal message is nearly free, which is what makes a welcome series, a monthly newsletter and a long nurture sequence affordable at all.

Is SMS marketing legal? The rules as published

Both channels are legal with consent and illegal in bulk without it, and the rules for texts are stricter. What follows is the published position in the US and the UK, with the sources, and it is not legal advice: the penalties are large enough that a business with any doubt should ask a lawyer before its first send.

Texts in the US. The Telephone Consumer Protection Act rules, at 47 CFR 64.1200, require prior express written consent before a marketing text is sent with an automated system. The same section bars telephone solicitations before 8 a.m. or after 9 p.m. in the recipient's local time, and some states set narrower hours. Under the FCC's 2024 revocation order, in force from 11 April 2025, a person can revoke consent by any reasonable means (the word STOP, but also QUIT, CANCEL, UNSUBSCRIBE or a plain-English sentence) and the sender must honour it within a reasonable time not exceeding 10 business days. On top of the law, the carriers' own code, CTIA's Messaging Principles and Best Practices (May 2023 edition, read 24 September 2026), says a number used for business messaging should be verified before it is text-enabled, and that a person should be able to opt out at any time, by text, call or email.

Email in the US. The CAN-SPAM Act, in the FTC's compliance guide (read 24 September 2026), requires accurate header and routing information, a subject line that does not mislead, a clear statement that the message is an advertisement, your valid physical postal address, a clear explanation of how to opt out, and that you "honor a recipient's opt-out request within 10 business days". The guide puts the penalty at up to $53,088 per email in violation. Note that CAN-SPAM does not require opt-in consent; the platforms and the mailbox providers do, which is a large part of why unwanted email goes to spam (see why your emails go to spam).

Both channels in the UK and the EU. The UK's Privacy and Electronic Communications Regulations, in the ICO's guidance, treat a text and an email alike as "electronic mail" and require consent for marketing to individuals, with one exception, the soft opt-in for existing customers who were offered a chance to refuse when their details were collected and in every message since. The EU's ePrivacy rules take the same shape, and the GDPR sets the standard consent has to meet: freely given, specific, informed, and as easy to withdraw as to give.

Consent for texts is a record you can show, not a box you remember ticking. Build it in this order before the first campaign.

The practical version, for a text programme:

1. Collect the number with a separate, unticked box whose wording names texting, your business name, roughly how often, and that message and data rates may apply. A number typed into a checkout for delivery updates is not consent to marketing texts.

2. Keep the record: the date, the form, the wording shown. This is what you produce if a complaint arrives.

3. Send a confirmation text that says who you are and how to stop and get help. Many platforms make this a double opt-in, and it is worth having.

4. Make STOP work automatically, and treat any plain-English refusal the same way.

5. Honour every opt-out within 10 business days at most. On both channels the same number applies; on a text the expectation is minutes.

6. Send in the recipient's daytime, using their local time when the list spans time zones.

When both is the right answer, and the order to send them

The strongest use of the two channels is to run them in sequence. For a sale, a launch or an event:

1. Email, two or three days before. The full story: what, why, pictures, the terms. This is the message people forward and search for later.

2. Email, the morning it starts, to the whole list. A shorter version with one link. If your list needs a better send time, test it rather than guess.

3. Text, a few hours before it ends, to the subset who opted in to texts. One sentence, the deadline, one link. Never the same words as the email at the same time: it doubles the cost, the reader has seen them, and the text is the one that gets the STOP.

4. Nothing else by text. One text per campaign, and two to four texts a month across all campaigns, is our rule of thumb rather than a measured figure. The STOP rate per send will tell you when yours is lower.

Measure the sequence on the same metric at every step, clicks per 1,000 sent or revenue per send, so the text is judged against the email on the same terms. A text that adds no clicks the email did not already get is a cost with no return, and the sequence tells you that within a campaign or two.

Choosing the software for each channel

The two channels are different enough that the checklist you judge a platform on is different too, even when one product does both.

For texting, the rows on our SMS marketing software listing that carry the rules above are automatic STOP handling, quiet hours enforcement and toll-free and 10DLC numbers: a platform without the first two puts the compliance work on you, and one without the third cannot get a US local number delivered. Two-way messaging inbox matters if replies are the action ("C" to confirm), and trackable short links are the only way a text can be measured on clicks.

For email, the rows on the email marketing software listing that matter most for this decision are double opt-in (the consent record), automated email sequences (the welcome series and the nurture that texts are too expensive for), inbox preview and spam testing, and a preference center, which gives a reader a way to have less without leaving.

Start with the list you have. If the texting column of your customer records is short, build it with the consent steps above before buying anything. When the list is there, open the SMS marketing software listing and check each product against the rows named here.