Ask any marketing team about SMS and the first objection is usually cost. "It's more expensive per message than email." That is technically true — but it misses the point entirely. What matters is not cost per message; it is cost per conversion. And on that metric, SMS wins convincingly.
Cost per conversion: the real comparison
According to Omnisend's 2023 analysis of e-commerce marketing data, SMS delivers a return that justifies its per-message premium:
- SMS click-through rate: 7.6% (compared to email at 1.8%)
- SMS conversion rate from automated messages: substantially higher than campaign emails
- Automated SMS generates 26% of all SMS orders from just 13% of sends
When you factor in the dramatically higher engagement and conversion rates, the effective cost per conversion for SMS is typically lower than email, paid social, and direct mail despite the higher per-unit cost.
Channel-by-channel comparison
SMS vs email. Email is essentially free to send, but average open rates of 20-25% and click rates of 1-2% mean you need a very large list to drive meaningful conversions. SMS marketing achieves 98% open rates and 7-8% click rates, meaning a list one-tenth the size can generate comparable results.
SMS vs paid social. The average cost per click on Facebook and Instagram advertising in the UK ranges from 50p to over two pounds depending on the industry. An SMS to an opted-in customer costs a fraction of that and arrives directly in their message inbox with no algorithm deciding whether to show it.
SMS vs direct mail. A single piece of direct mail costs 50p to over one pound when you factor in design, print, and postage. Response rates for direct mail average 2-5%. SMS delivers far higher response rates at a fraction of the cost, with instant delivery rather than a two to three day wait.
The hidden cost advantages
Beyond per-message economics, SMS has structural cost advantages that are easy to overlook:
- No app development costs — unlike push notifications, SMS does not require building and maintaining a mobile app
- No platform fees for recipients — customers do not need to download anything or create an account
- No algorithm filtering — every message is delivered directly to the inbox, not filtered by an engagement algorithm
- Immediate delivery — no production lead time, no print runs, no postal delays
- Minimal creative costs — a well-written 160-character message does not require a design team
How to calculate your SMS ROI
To understand the true value of SMS for your business, calculate your cost per conversion rather than cost per message:
- Total SMS spend — your message costs for a campaign or period (check our pricing page for current rates)
- Total conversions — sales, bookings, sign-ups, or whatever action your message drives
- Cost per conversion — divide total spend by total conversions
- Compare — benchmark against your email, paid social, and direct mail cost per conversion
Most businesses that run this analysis find that SMS delivers their lowest cost per conversion of any channel, particularly for time-sensitive offers and appointment reminders where the immediacy of SMS drives faster action.
Making every message count
The key to maximising SMS ROI is sending the right message to the right person at the right time. Targeted, well-timed messages to engaged audiences consistently outperform broadcast blasts to large lists. Segment your audience, personalise your content, and respect frequency preferences. Done well, SMS is not just the best value channel — it is the highest-performing one.
Ready to see the ROI for yourself? Register for a free Faretext account and we will give you 25 credits to test with.
Frequently asked questions
Is SMS really cheaper than email when you look at cost per conversion?
In most cases, yes. While each SMS costs more to send than each email, the 98% open rate and 7-8% click-through rate mean far fewer messages are needed to achieve the same number of conversions. The cost per actual result is typically lower with SMS.
How much does a business SMS cost in the UK?
UK SMS pricing typically ranges from 2-5p per message depending on volume and provider. At Faretext, our pricing is fully transparent with no hidden fees for delivery reports, API access, or inbound messages.
Can I combine SMS with other marketing channels?
Absolutely. SMS works best as part of a multi-channel strategy. Use email for detailed content, social media for brand awareness, and SMS for time-sensitive offers and reminders that demand immediate attention.
Sources: Omnisend — 2023 Email, SMS, and Push Report, Mobile Marketing Association
