A single SMS message supports 160 characters using standard GSM-7 encoding, but this drops to just 70 characters when you include emojis, special characters, or non-English text that requires Unicode. CRITICAL: One emoji forces the entire message into Unicode, reducing the limit from 160 to 70 characters. Extended characters like ^ { } [ ] ~ \ and the euro sign count as 2 characters each. iMessage has no limit (internet-based) but falls back to SMS for non-Apple devices.

This guide explains SMS character limits, encoding types, and strategies for effective text messaging.

SMS Character Limits by Encoding

Understanding GSM-7 Encoding

What GSM-7 Includes

Standard characters (160-char limit):

• A-Z, a-z (all English letters)
• 0-9 (numbers)
• Basic punctuation: . , : ; ! ? " ’ - / ( ) & + = # * @ $ % _
• Space

Extended GSM characters (count as 2 characters):

• ^ ~ [ ] { } \ | €

Example: “Your order #12345 is confirmed. Delivery on Tuesday.” = 53 characters (fits easily)

When GSM-7 Works

Use for:

• Basic English messages
• Order confirmations
• Appointment reminders
• Simple notifications
• Any message without emojis or special characters

Understanding Unicode Encoding

What Triggers Unicode

Unicode required for:

• Emojis (any emoji)
• Non-Latin scripts (Chinese, Arabic, Hebrew, etc.)
• Special symbols not in GSM-7
• Accented characters in some contexts

The Emoji Impact

Critical understanding: ONE emoji switches your entire message to Unicode.

Before emoji (GSM-7): “Your package ships today!” = 25 characters of 160

With emoji (Unicode): “Your package ships today! 📦” = 27 characters of 70

The math:

• Without emoji: 160 - 25 = 135 chars remaining
• With emoji: 70 - 27 = 43 chars remaining

Adding one emoji cost you 92 potential characters.

Multi-Part Messages

How Segments Work

When you exceed single message limits: Messages are split into segments joined by the receiver’s phone.

GSM-7 multi-part:

• First segment: 153 characters
• Each additional: 153 characters
• 7 characters used for concatenation header

Unicode multi-part:

• First segment: 67 characters
• Each additional: 67 characters
• 3 characters used for concatenation header

Segment Calculations

Example with GSM-7:

Example with Unicode:

Cost Implications

SMS marketing: Most providers charge per segment

A 200-character message:

• In GSM-7: 2 segments = 2x cost
• In Unicode: 3 segments = 3x cost

MMS vs. SMS

MMS Limits

Text in MMS: Up to 1,600 characters Plus: Images, audio, video attachments

When to use MMS:

• Marketing with visuals
• When character limits are too restrictive
• Rich media content

Considerations:

• Higher cost per message
• Not all recipients support MMS
• Larger file sizes

SMS Marketing Best Practices

Staying Within Limits

Target: 160 characters or fewer (ideally under 140 for buffer)

Why under 140:

• Room for personalization (names, etc.)
• Carrier variations
• Link shorteners may expand

Writing Concise SMS

Techniques:

• Remove unnecessary words
• Use abbreviations sparingly (if audience expects them)
• Prioritize essential information
• Single call-to-action

Example transformation: Before (180 chars): “Hello! We wanted to let you know that your appointment is scheduled for tomorrow at 2:00 PM. Please reply YES to confirm or call us to reschedule.”

After (155 chars): “Hi! Your appt is tomorrow at 2PM. Reply YES to confirm or call to reschedule. Questions? 555-1234”

Link Handling

Short URLs:

• Bit.ly, TinyURL, or branded shorteners
• Most SMS links: 20-30 characters
• Some carriers expand shortened URLs

Best practice: Test your messages on actual phones to see final character count.

Special Characters to Watch

Characters That Use 2 Slots (GSM Extended)

These count as 2 characters: ^ { } [ ] ~ \ € |

Example: “Price: €50 [limited time]” = 26 characters (not 24)

• € counts as 2
• [ counts as 2
• ] counts as 2

Smart Quotes and Formatting

Danger zone: Smart quotes from word processors

These trigger Unicode:

• " " (curly quotes) → Use " " (straight quotes) instead
• ’ ’ (curly apostrophe) → Use ’ instead
• — (em dash) → Use - (hyphen) instead

Best practice: Type SMS in plain text editors to avoid hidden formatting.

Technical Details

Why 160 Characters?

Historical reason: Based on telecom protocol specifications from the 1980s 7-bit encoding: 140 bytes × 8 bits ÷ 7 = 160 characters

Carrier Variations

Not all carriers identical:

• Some handle concatenation differently
• International messages may vary
• Premium rate numbers have different limits

Testing: Always test with your specific carrier/provider.

Frequently Asked Questions

Why does one emoji ruin my character limit?

The entire message must use a single encoding type. Even one Unicode character (like an emoji) forces the whole message into Unicode mode, dropping the limit from 160 to 70.

Can I use emojis in SMS marketing?

Yes, but understand the trade-off. You’ll have fewer characters and potentially higher costs due to multiple segments. Some marketers find emojis boost engagement enough to justify the cost.

What happens if I exceed the character limit?

Your message is split into multiple segments. Receivers typically see it as one message, but you’re charged for each segment.

Do spaces count as characters in SMS?

Yes, every space counts as one character toward your limit.

How do link shorteners affect character count?

Link shorteners reduce visible URL length, but some carriers expand them to full length. Test your messages to verify final character count.

Is there a difference between SMS and iMessage limits?

iMessage (Apple to Apple) has no character limit because it’s internet-based and doesn’t follow SMS encoding rules. However, messages to non-Apple devices or when data is unavailable fall back to SMS limits (160 GSM-7 or 70 Unicode).

Key Takeaways

• Standard SMS: 160 characters (GSM-7 encoding)
• With emojis/Unicode: Only 70 characters
• CRITICAL: One emoji forces entire message into Unicode, reducing limit from 160 to 70
• Multi-part messages: 153 chars per segment (GSM-7) or 67 (Unicode)
• Extended characters (^ { } [ ] ~ \ € |) count as 2 characters each
• iMessage: No character limit (internet-based), falls back to SMS for non-Apple
• SMS marketing: Stay under 140 characters for safety margin

Conclusion

SMS character limits are more complex than they first appear. The 160-character standard works until you add a single emoji, which drops you to 70 characters and can double or triple your per-message cost. For SMS marketing, understand these encoding rules, test messages before campaigns, and make every character count. Try our free letter counter → to verify your SMS messages fit within the appropriate limits before sending.