The short version: SMS marketing works by getting a customer's mobile number with proper consent, then sending them short, timed texts through a platform like SimpleTexting, Textedly or Klaviyo's SMS add-on, usually costing between 2p and 6p per message plus a monthly platform fee. It gets read almost immediately (industry figures put open rates around 98 percent, most within three minutes) which is why it beats email for anything urgent, but it also burns through your list's goodwill faster than any other channel if you treat it like free advertising instead of the interruption it is.
What SMS marketing is, stripped of the hype
Forget the webinars that make this sound complicated. SMS marketing is you sending a text message to a list of customers who said yes to getting them, using software that lets you send to hundreds or thousands of people at once instead of one by one. That's it. The platform (SimpleTexting, EZ Texting, Textedly, TextAnywhere in the UK, or an SMS module bolted onto something like Klaviyo) handles the sending, the opt-outs, and the compliance paperwork you'd never manage manually.
The mechanics are simple. You collect numbers, usually through a signup form, a checkout box, a QR code on a receipt, or a keyword texted to a shortcode. You segment that list. You write short messages, 160 characters if you want them to count as one text rather than being split (and billed) as two or three. You send. People reply, click, buy, or ignore you, and the platform tracks all of it.
Where small businesses go wrong is thinking of it as a smaller, cheaper version of email. It isn't. Email sits in an inbox you check when you feel like it. A text lands on the one screen most people check within minutes of it lighting up, often while they're at the dinner table or in a meeting. That's the entire appeal of SMS and also its biggest risk. You are asking to be let onto the most personal device someone owns.
The numbers that decide whether it's worth doing
Here's what I tell clients when they ask if SMS is "worth it" for a business their size:
- Open rates: commonly cited around 98 percent, compared with email's 20 to 30 percent for a well-run list.
- Response or click rates: SMS regularly sees click-through in the high teens (some studies put it near 19 percent), against email's 2 to 5 percent.
- Cost per message: in the UK, expect roughly 3 to 6 pence per SMS depending on volume and provider. In the US, closer to 1 to 3 cents through a platform, more through some all-in-one CRMs that mark it up.
- Platform fees: a small business sending a few hundred texts a month is typically looking at £20 to £90 a month for the software itself, on top of per-message costs.
- Unsubscribe rate: SMS opt-out rates run far higher per campaign than email if you send too often. I've seen a single badly timed Saturday morning promotional text cost a client 4 percent of their list in one afternoon.
Run the maths before you commit. A list of 2,000 subscribers, sent one campaign a week at, say, 4p a message, is roughly £320 a month in sending costs alone, before the platform fee. If that campaign is generating even a handful of £40 bookings a week, it pays for itself. If it isn't, you're just paying to annoy people.
A real example: the gym that nearly ruined its own list
A client of mine, a small independent gym in Kent with about 900 members, wanted SMS reminders for expiring memberships and last-minute class spaces. Good use case. useful to the customer. Open rates on those were extraordinary, well over 95 percent, because the messages were things people wanted: "Your spin class at 6pm has 2 spots left" or "Your membership renews in 3 days, tap to update your card."
Then the marketing manager got excited and started adding a weekly "flash sale on protein shakes" text on top. Within six weeks, opt-outs had crept from near zero to about 60 people, roughly 7 percent of the list, and several members complained directly to staff at the front desk, which is worse than any unsubscribe click because it damages the actual relationship. We pulled the promotional texts back to once a month, kept the operational reminders as they were, and the list stabilised. The lesson wasn't that SMS doesn't work. It was that the same channel that gets read in three minutes also gets resented in three seconds if it's the wrong message at the wrong time.
Setting it up: the actual steps
This is the part most guides gloss over. Here's what setting up SMS marketing looks like in practice for a small business:
- Step 1: Pick a platform. For under 5,000 contacts, something like Textedly or SimpleTexting is enough. If you already run email through Klaviyo or Mailchimp, check their SMS add-on first, it saves you managing two systems.
- Step 2: Get a number or shortcode. Most platforms give you a dedicated number or shared shortcode. Dedicated numbers cost more (often £10 to £30 a month extra) but look less like spam.
- Step 3: Build consent into every collection point. Checkout page, in-store signup sheet, website pop-up, all need an explicit, unticked checkbox that says exactly what they're signing up for. "Get 10% off your next order by text" is fine. Pre-ticked boxes or vague "join our list" language is where businesses get caught out.
- Step 4: Set up your keywords and auto-replies. A working STOP keyword is a legal requirement, not a nice-to-have, in both the UK and US.
- Step 5: Segment before you send anything. New customers, repeat customers, and lapsed customers should never get the identical text. Even a basic two-way split makes open and click rates noticeably better.
- Step 6: Write short, and test the send time. Late morning and mid-afternoon on weekdays consistently outperform evenings and weekends for most retail and service businesses I've worked with.
- Step 7: Track replies as a sales channel, not just a metric. Someone replying "YES" to a booking text is a live lead. Treat it like one.
The consent problem nobody wants to dwell on
Here's the bit that gets skipped in most "how SMS marketing works" articles: this is one of the most heavily regulated forms of marketing a small business can run, and enforcement is not just aimed at big companies. In the UK, unsolicited marketing texts fall under PECR, policed by the ICO, and fines have hit small firms, not just corporations, for sending texts to numbers scraped or bought without direct consent. In the US, the TCPA has produced settlements running into hundreds of thousands of dollars against companies with a fraction of the revenue of a national chain. Nobody thinks it'll be them until it is.
The uncomfortable truth is that a lot of small businesses build their SMS list on soft consent, a form that technically mentions texts somewhere in the small print, and hope nobody checks. That works fine right up until a customer complains, or a competitor reports you, or your provider gets audited and finds your opt-in records don't hold up. Getting explicit, documented consent, with a timestamp and the exact wording shown, isn't paperwork for its own sake. It's the only thing standing between you and a fine that costs more than five years of SMS campaigns combined.
What to send, and how often
The businesses that get the best results from SMS treat it as a small number of high-value moments, not a broadcast channel. That means:
- Order and booking confirmations (highest open rates, near-zero opt-outs).
- Appointment reminders, especially for anything with a no-show cost, salons, clinics, tradespeople.
- Time-sensitive stock alerts ("back in stock" or "last few left").
- Genuine, occasional offers, capped at once or twice a month at most for anything purely promotional.
What doesn't belong in a text: long-form content, anything that needs explaining, or daily contact of any kind. If you wouldn't be comfortable getting the same message from a stranger's number on your own phone at 9am on a Tuesday, don't send it.
Where SMS fits alongside everything else you're doing
SMS shouldn't sit on its own. It works best as the fast, short-form layer sitting on top of email and social, reserved for the messages that need a reply within the hour. If you're already stretched thin deciding which channels deserve your time at all, it's worth reading through whether a channel like Pinterest still earns its place in a small business marketing mix before adding one more platform to manage.
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The same discipline applies to picking the SMS provider itself. There are dozens of near-identical tools claiming the best deliverability and the lowest fees, and most of the comparison pages reviewing them are written by the tools themselves. I'd rather work from a framework for choosing marketing tools when everything on the surface looks the same than trust a "top 10 SMS platforms" listicle.
If you're wondering whether AI can take some of the writing and segmentation work off your plate here, it can help with drafting variants and predicting send times, but deciding what gets sent and to whom is squarely the kind of judgment call covered in which parts of marketing AI is good at. And consent management, tone, and the decision about when to text a customer rather than automate the message entirely belongs firmly on the list of marketing tasks you should never fully automate. A machine deciding your opt-in wording or your unsubscribe handling is exactly how businesses end up on the wrong side of the ICO.
Worth noting too: the trust signals that make someone opt in to your texts in the first place usually come from somewhere else first, a review, a recommendation, proof someone else had a good experience. That's why product reviews matter more than most small businesses realise when it comes to getting that first, willing signup rather than a reluctant one.
Frequently asked questions
How much does SMS marketing cost for a small business?
Expect a platform fee of roughly £20 to £90 a month plus 2p to 6p per message sent in the UK, or 1 to 3 cents per message in the US. A business sending 1,000 texts a month should budget somewhere between £40 and £150 all in, depending on the provider and number type.
Is SMS marketing legal without an app or website?
Yes, but only with proper consent collected somewhere, in store on a signed form, over the phone with a recorded agreement, or through a text keyword sign-up. You don't need a website, but you do need a clear record of who agreed to what and when.
How often should a small business send marketing texts?
Operational texts (confirmations, reminders) can go out as often as they're needed. Pure promotional texts should stay to once or twice a month at most. Go beyond that and opt-out rates climb fast, often noticeably within a matter of weeks.
Does SMS marketing work better than email?
For urgency and open rates, yes, comfortably. For storytelling, education, or anything that needs more than a couple of lines, email still does the job SMS can't. The two work best side by side rather than as a straight replacement.
Related reading: How to Plan a Month of Social Content Without a Big Team and Why Your LinkedIn Account Got Restricted (and How to Fix It).
For the bigger picture, see my full guide to digital marketing.
