SMS Character Limits & Segmentation Explained (2026 Guide)

Here's something that caught me off guard when I first started working with SMS marketing: that 160-character limit isn't as simple as it sounds. Add one emoji, and suddenly your message splits into multiple segments — and each segment costs money. I learned this the expensive way.

Let me break down everything I've learned about SMS character limits, encoding quirks, and how to keep your messages in a single segment without sacrificing your message.

SMS Character Limit Overview

Here's a quick reference for SMS character limits:

The character limit depends entirely on which characters you include in your message. Using only basic characters (letters, numbers, and common punctuation) allows for 160 characters. Including any special characters, emojis, or non-Latin letters automatically switches to Unicode encoding with a 70-character limit.

GSM-7 Encoding: 160 Characters

GSM-7 (Global System for Mobile Communications 7-bit alphabet) is the default encoding for SMS messages. It uses 7 bits per character, allowing 160 characters to fit within the 1120-bit SMS payload.

GSM-7 Supported Characters

The GSM-7 character set includes:

• Letters: A-Z, a-z (basic Latin alphabet only)
• Numbers: 0-9
• Punctuation: . , : ; ! ? " ' ( ) - / + = < >
• Symbols: @ # $ % & * _ space
• Special: Line break, carriage return

Extended GSM-7 Characters

Some characters use an escape sequence and count as 2 characters in GSM-7 encoding:

• Curly braces: {} (2 characters each)
• Square brackets: [] (2 characters each)
• Backslash: \ (2 characters)
• Caret: ^ (2 characters)
• Euro sign: € (2 characters)
• Tilde: ~ (2 characters)
• Pipe: | (2 characters)

Be aware of these extended characters when calculating message length. Using them reduces your effective character count within the 160-character limit.

Unicode Encoding: 70 Characters

When your SMS contains any character outside the GSM-7 character set, the entire message automatically switches to Unicode (UCS-2) encoding. This uses 16 bits per character, reducing the limit to 70 characters per segment.

Characters That Trigger Unicode

• Emojis: Any emoji forces Unicode encoding
• Non-Latin alphabets: Chinese, Japanese, Korean, Arabic, Hebrew, Cyrillic, Greek, Thai
• Accented characters: é, ñ, ü, ç, å (beyond basic Latin)
• Special symbols: ™, ©, °, smart quotes (“”), em dashes (—)

The Emoji Cost

Emojis deserve special attention because they're commonly used but significantly impact SMS costs:

• A single emoji forces the entire message to Unicode
• Most emojis count as 2 characters in Unicode encoding
• Complex emojis (skin tones, gender variations, family groups) can count as 4-7 characters
• A 150-character message with one emoji becomes a 2-segment message instead of 1

Before adding emojis to business SMS, calculate whether the engagement benefit outweighs the cost of additional segments.

How SMS Segmentation Works

When your message exceeds the single-segment limit (160 GSM-7 or 70 Unicode), it gets split into multiple segments. Each segment is transmitted separately and reassembled on the recipient's device.

User Data Header (UDH)

Multi-part messages require a User Data Header that tells the receiving device how to reassemble the segments. This header consumes characters from each segment:

• GSM-7: 7 characters reserved for UDH (160 - 7 = 153 usable)
• Unicode: 3 characters reserved for UDH (70 - 3 = 67 usable)

Segment Calculation Examples

Most SMS providers charge per segment, so a 161-character GSM-7 message costs twice as much as a 160-character message. Use our character counter to optimize your message length before sending.

SMS vs MMS: When to Switch

Understanding when to use MMS (Multimedia Messaging Service) instead of SMS can save costs and improve message delivery.

MMS Advantages

• Higher character limit: Up to 1,600 characters for text
• Rich media: Images, videos, audio files, GIFs
• No segmentation: Long messages send as one unit
• Subject line: Optional subject field available

MMS Limitations

• Higher cost: Typically 3-5x more expensive than SMS
• Data required: Recipient needs data connection
• File size limits: Usually 300KB-600KB maximum
• Slower delivery: Takes longer than SMS
• Variable support: Not all carriers/devices handle MMS well

When to Choose MMS

Consider MMS when:

• Your message requires images or video for context
• Text would exceed 3+ SMS segments
• Visual content significantly improves engagement
• Your audience has reliable data connectivity

Carrier Differences

While SMS standards are universal, carriers implement them differently, affecting character limits and delivery.

Major US Carriers

• Verizon: Standard 160/70 limits; concatenates up to 7 segments
• AT&T: Standard limits; supports up to 10 segments
• T-Mobile: Standard limits; may convert long SMS to MMS automatically
• US Cellular: Standard limits; varies by device

International Considerations

When sending SMS internationally:

• Sender ID support: Varies by country (alphanumeric IDs not supported everywhere)
• Character encoding: Some countries default to Unicode
• Delivery time: International routes may have delays
• Costs: International SMS often priced higher per segment

RCS Messaging

Rich Communication Services (RCS) is replacing SMS on many Android devices, offering longer messages, read receipts, and rich media without MMS costs. However, RCS adoption is still limited, and fallback to SMS remains essential for universal reach.

Business SMS Best Practices

For businesses sending SMS at scale, optimizing character usage directly impacts costs and campaign effectiveness.

Cost Optimization Strategies

1. Stick to GSM-7: Avoid emojis and special characters when possible
2. Target 160 characters: Keep messages within single-segment limits
3. Use URL shorteners: Replace long links with shortened versions
4. Abbreviate wisely: Common abbreviations are acceptable if clear
5. Test before bulk send: Verify character count and encoding

Message Content Guidelines

• Lead with value: Put the most important information first
• Include clear CTA: Tell recipients what to do next
• Identify yourself: Brand name should appear early
• Include opt-out: Required for marketing messages (e.g., "Reply STOP to unsubscribe")

Template Examples

Appointment reminder (126 characters, GSM-7):

Hi [Name], reminder: Your appointment at [Business] is tomorrow at 2pm. Reply YES to confirm or call 555-1234 to reschedule.

Order notification (142 characters, GSM-7):

[Brand]: Your order #12345 has shipped! Track at bit.ly/track123. Estimated delivery: Jan 25. Questions? Reply to this message.

A/B Testing Tips

• Test with and without emojis to measure engagement vs cost
• Compare short (under 100 chars) vs full 160-character messages
• Measure click-through rates on different CTA placements
• Track opt-out rates by message length and content type

Frequently Asked Questions

What is the standard SMS character limit?

The standard SMS character limit is 160 characters when using GSM-7 encoding, which supports basic Latin letters, numbers, and common punctuation. If your message contains only these characters, you get the full 160 characters per segment. Messages longer than 160 characters are automatically split into multiple segments.

Why is my SMS limited to 70 characters?

When your message contains any Unicode character—including emojis, non-Latin alphabets (Chinese, Arabic, Cyrillic, etc.), or special symbols—the SMS automatically switches to UCS-2 encoding. This encoding uses 16 bits per character instead of 7, reducing the limit to 70 characters per segment. Even a single emoji forces the entire message to use this reduced limit.

What is SMS segmentation?

SMS segmentation occurs when your message exceeds the single-segment limit. The message is split into multiple parts, each sent as a separate SMS. A User Data Header (UDH) is added to each segment to help the recipient's device reassemble them correctly. This header uses 7 characters (GSM-7) or 3 characters (Unicode), reducing usable space to 153 or 67 characters per segment respectively. Most providers charge per segment, so a 161-character message costs twice as much as a 160-character message.

How do emojis affect SMS character count?

Emojis have a significant impact on SMS. First, using any emoji forces the entire message to switch to Unicode encoding, dropping the limit from 160 to 70 characters. Second, most emojis count as 2 characters in Unicode. Complex emojis with modifiers (skin tones, gender variants, or sequences like family emojis) can count as 4-7 characters. A simple message that fits in one segment without emojis might become 2-3 segments with emojis added.

What is the difference between SMS and MMS?

SMS (Short Message Service) is text-only with strict character limits (160 GSM-7 or 70 Unicode). MMS (Multimedia Messaging Service) supports images, videos, audio, and longer text (up to 1,600 characters). MMS costs more (typically 3-5x) and requires a data connection, but it's often more cost-effective for long text messages that would require 3+ SMS segments. Choose SMS for short notifications and MMS for rich media or lengthy content.

How can I check my SMS character count?

Use our free character counter tool to check your message length before sending. It shows real-time character count, helping you stay within single-segment limits and optimize your SMS costs. Pay special attention to characters that might trigger Unicode encoding or count as double.