Every UK small business owner faces the same question when it comes to marketing: where do I spend my limited budget for maximum return? SMS marketing and email marketing are both powerful tools — but they work very differently and suit different situations.
The Headline Numbers
SMS messages are read within 3 minutes of receipt on average. Emails sit in inboxes for hours — or days — before being opened, if they're opened at all. But open rate isn't the only metric that matters.
SMS Marketing — Strengths and Weaknesses
Strengths:
- 98% open rate — almost guaranteed to be seen
- Read within 3 minutes on average
- Extremely low cost — as little as 4p per message
- No design required — simple plain text works perfectly
- Immediate action — customers act on SMS within hours
- Perfect for time-sensitive promotions and flash sales
- High trust — customers don't expect spam via SMS
Weaknesses:
- Limited to 160 characters (or linked content)
- Can feel intrusive if overused — maximum 2–4 per month
- Requires phone numbers (not always easy to collect)
- Less suited to complex information or long content
Email Marketing — Strengths and Weaknesses
Strengths:
- Rich format — images, buttons, full design possible
- Can share detailed information, menus, updates
- Very low cost — often free for small lists
- Easy to automate sequences and journeys
- Better for B2B communication and longer sales cycles
- Great for newsletters, product launches, and storytelling
Weaknesses:
- Only 20% average open rate — 80% never see it
- Spam filters increasingly aggressive
- Crowded inboxes mean high competition
- Takes longer to see results
Which Should UK Small Businesses Use?
The honest answer is both — but for different purposes. They complement each other rather than compete.
Use SMS for: Flash promotions, appointment reminders, time-sensitive offers, winning back lapsed customers, announcing special events. The immediacy of SMS is unmatched.
Use email for: Monthly newsletters, detailed product information, onboarding sequences, loyalty programme communications, and B2B outreach where a professional format matters.
The ROI Comparison
Sending 500 SMS messages at 4p each costs £20. If even 2% convert on a £25 average order, that's 10 orders = £250 revenue from £20 spend — a 12.5× return.
Email can deliver similar returns for the right business and audience, but typically requires larger lists and more sophisticated content to achieve the same conversion rates as SMS.