🔍 How to Check If an Icon Is Costing You Double: SMS Encoding Tools Explained

In the ever-evolving world of SMS marketing, every character counts. Literally.

While icons and emojis can supercharge engagement, they may also silently bloat your SMS cost. Many marketers unknowingly send messages that get split into multiple parts—not because they’re long, but because of a hidden encoding switch.

This guide demystifies SMS encoding, how icons impact message cost, and which tools you can use to test, optimize, and save money.

📲 The Anatomy of an SMS

Before we dive into icons, it’s crucial to understand how SMS messages are built.

🧱 1. SMS Character Limit Basics:

• Standard SMS (GSM-7) = 160 characters max

• Unicode SMS (UCS-2) = 70 characters max

If your message uses even one Unicode character (including most emojis), the entire SMS switches to UCS-2, reducing your character limit to 70.

Messages longer than these limits are split and sent as multi-part messages:

Encoding	Single Part	Multipart (Segment Size)
GSM-7	160 chars	153 chars per part
UCS-2	70 chars	67 chars per part

So yes—a single emoji can double your cost.

🧠 Why Icons Affect Cost (Even if Your Message Is Short)

Let’s say your SMS reads:

🎰 Your bonus is ready – claim your free spins now!

That short sentence might look fine, but it contains an emoji. That emoji is encoded in UCS-2, so even though the message is under 70 visible characters, it’s now billed as Unicode. That’s 1 message per 70 characters, not 160.

If you added just a few more words, it could get split into two full Unicode SMS parts, meaning double the price.

📉 Cost Comparison Example

Message	Encoding	Characters	Cost (Parts)
Your bonus is ready – claim now!	GSM-7	39	1
🎰 Your bonus is ready – claim now!	UCS-2	40	1
🎰 Claim your bonus + free spins today!🔥	UCS-2	72	2

A simple emoji at the start and end pushed that last one over the 70 char UCS-2 limit, triggering 2 full messages billed.

🛠 Tools to Check SMS Encoding & Costs

You don’t have to guess. These tools tell you exactly how your message will behave:

1. Twilio’s SMS Segment Calculator

• https://twilio.com

• Paste your SMS → see encoding, segment count, and costs.

• Highlights Unicode characters.

2. Messente SMS Length Calculator

• https://messente.com/tools/sms-length-calculator

• Real-time encoding detection

• Breakdown of segments and part counts

3. D7Networks SMS Character Checker

• https://d7networks.com

• Shows actual byte size per character

• Detects special GSM characters that may also trigger UCS-2

4. GSM 03.38 Character Set Reference Tool

• Lists all characters supported in GSM-7

• Helps you manually compare which symbols are GSM-safe (✔️ ✅ 👍) vs UCS-2-only (🚀 🤑 ❤️)

5. SMSBump Preview Tool (Shopify Users)

• Built-in for users of SMSBump/Yotpo

• Detects emoji encoding and calculates message cost dynamically

🧮 GSM-7 vs Unicode: The Technical Side

What Is GSM-7?

• A 7-bit alphabet supporting Latin characters and basic symbols

• Standard SMS encoding used by most phones

• Allows 160 characters per SMS

What Is UCS-2?

• A Unicode format used when characters outside GSM-7 appear

• Includes most emojis, Asian scripts, currency symbols, etc.

• Limits each message to 70 characters

Common Characters That Trigger UCS-2:

• Emojis: 🎰 🔥 🎁 😍 🙌

• Fancy punctuation: “ ” — …

• Non-standard currency symbols: ₹ ¥ ₿

• Accented letters (if not fallback-mapped): é ü ñ

✅ Tips to Use Icons Without Breaking the Bank

1. Use GSM-Compatible Icons

   • Characters like @, !, #, and € are part of GSM-7

   • Unicode-safe icons include basic check marks: ✅ ✔️

2. Test Every Message Before Sending

   • Use tools above to verify encoding and cost

   • Always test both full and spintax variations

3. Keep Icons Near Start or CTA

   • Focus icon placement where it adds value (subject, call-to-action)

   • Avoid icon “padding” (e.g., 🎰🎰🎰FREE SPINS🎰🎰🎰)

4. Stay Under 70 Characters If Using Unicode

   • Limit Unicode message to 1 part to avoid unnecessary cost

   • Combine clear CTA + 1 icon

5. A/B Test with and Without Icons

   • Compare CTR, ROI, and unsub rates

   • Sometimes simple text performs better depending on audience

🧠 Strategic Takeaway

Using emojis and icons in SMS isn’t a “yes or no” decision—it’s a budget vs impact calculation.

Icons:

• Draw attention

• Add personality

• Highlight urgency or rewards

But they also:

• Trigger Unicode

• Reduce character limits

• Potentially double your send cost

Using the right tools, you can balance these forces—and make sure your marketing is both creative and cost-effective.

🧠 Summary: Smart SMS Icon Use Checklist

✅ Test message length and encoding before every campaign✅ Stick to 1–2 impactful icons max✅ Place icons with intent (CTA, emotion, structure)✅ Stay under 70 chars if using emojis✅ A/B test performance with & without icons✅ Use preview/calculator tools to catch costly surprises This blog post was written entirely by AI