When you send a text message that exceeds 160 characters, it is automatically broken down into multiple segments and then reassembled on the recipient's phone, appearing as a single, continuous message.
How Long Text Messages Are Processed
The standard SMS (Short Message Service) protocol was originally designed for messages up to 160 characters using the GSM 7-bit alphabet. When a message surpasses this limit, a process called concatenation comes into play.
- Splitting the Message: Your long text message is not sent as one large block. Instead, it is divided into smaller segments. For SMS, these segments are typically 153 characters long, rather than the full 160.
- Header Information: The reason for the 153-character segment size is that 7 characters of each segment are reserved for special instructions. These hidden characters tell the mobile carriers and the recipient's handset how to reconstruct the message in the correct order upon delivery.
- Reassembly: Once all the segments arrive, the recipient's phone uses these header instructions to seamlessly piece them together, so the user sees one complete, fluent long message, just as you typed it.
Impact on Messaging Experience
While concatenated messages generally appear as one on the recipient's device, there are a few practical implications:
- Cost Implications: Although it looks like a single message, you are often charged per segment by your mobile carrier. For example, a 300-character message might be billed as two separate SMS messages. It's wise to check your specific mobile plan details regarding long text messages.
- Character Set Variations: The 160-character limit applies to messages using the standard GSM 7-bit alphabet (which includes common English letters, numbers, and symbols). If your message contains special characters, emojis, or characters from other languages (like Cyrillic or Arabic), it might switch to a different encoding like Unicode (UCS-2), which significantly reduces the per-segment character limit, often to just 70 characters.
Practical Character Limit Breakdown
Understanding how your message length translates to segments can help manage costs and expectations:
| Character Count (GSM 7-bit) | Number of SMS Segments | Appears As |
|---|---|---|
| 1 - 160 | 1 | Single message |
| 161 - 306 | 2 | Single message (concatenated) |
| 307 - 459 | 3 | Single message (concatenated) |
| 460 - 612 | 4 | Single message (concatenated) |
Solutions for Very Long Messages
For exceptionally long messages, or if you frequently send texts with many special characters or emojis, consider using alternative messaging platforms that utilize internet data rather than traditional SMS, such as:
- Instant Messaging Apps: Applications like WhatsApp, Telegram, Signal, or Facebook Messenger offer virtually unlimited character counts and richer media sharing capabilities, as they rely on internet connectivity.
- Email: For very formal or lengthy communications, email remains a reliable option.
Ultimately, while exceeding the 160-character limit results in your text being segmented, modern mobile technology ensures it arrives as a unified message, maintaining the flow of conversation.
