Segments in initial messages and replies for SMS texts

Understanding Text Message Segments for SMS

In the realm of SMS communication, the concept of message segments plays a crucial role. Text messages are sent in segments, which are blocks of encoded characters. The length of a segment is determined by how much data each character uses when translated into readable text. These segments are crucial to review when creating messages, especially for those managing costs or ensuring optimal message delivery.


Segment Lengths

The default length for an SMS message is 160 characters for the first segment and 153 for any additional segments. Regular characters, also known as "7-bit encoded," count as one character each. However, some special characters are encoded differently and count as two characters in a segment. 

Using fancier characters and emojis will reduce the segment length further because explaining these characters through the messaging environment requires more data. Messages with these characters or emojis will limit each segment to a maximum of 70 characters for the first segment and 63 for any additional segment. You can read more about message encoding in our guide

Most modern cell phone carriers will reassemble multi-part text messages into one long text. However, older phones and some carriers may deliver these segments separately, potentially out of order. Some carriers even use indicators like (1/3), (2/3), (3/3), which consume an additional 7 characters.

NOTE - When copying and pasting your initial message from external sources like Word documents or Google Docs into ThruText, be aware that the original encoding may be transferred as well. This can affect segment length, potentially shortening it and causing your message to be split into more segments than intended. If you are on a per-segment payment plan, this can lead to higher costs. To avoid this issue, it is recommended to type out your initial message directly in ThruText.

Some organizations are charged per-segment. Monitoring the amount of segments saves them money!

Best Practices for Length

For the best user experience with your contacts, we highly recommend keeping your initial messages shorter to encourage conversation. Very long initial messages can impact deliverability by reducing throughput. Please refer to our guide for more tips on initial message creation.

Be wary of using emojis and other special characters in long scripts. Your target contacts will also appreciate it!

Keep in mind that recommended replies also have segments. We also have tips on recommended replies.

Preview feature for text messages

ThruText's Message Preview feature allows you to estimate the segments in your SMS messages. Please note that the length of custom attributes (e.g., texter's first or last name) in your script may affect this estimate. Nevertheless, this feature provides valuable insight into your message's length and how it will appear to contacts who receive message segments.

In the following example, the estimator shows that the current message uses one segment and has used 106 out of the 160 characters for that segment. This means there is space for approximately 54 more characters before the start of the next segment.  

Screenshot of a partially filled text input field beneath the header "Craft an Initial Message". Below the input box is an illustrated example of the text written in the input field.

Admins can create line breaks by holding down the "shift" and "enter" buttons at the same time. These are visible in the Message Preview and reduce the remaining characters in a segment.

NOTE - On MMS approved use cases, the above "Browse Media Library" option will appear for you to add media (a picture or GIF) to your initial message. Adding media will remove the segment count and revise the character limit for the message being sent.

To get an exact segment count for your message, consider using a tool like Sakari to calculate the exact message length, segment count, and encoding type. We recommend using the actual text that will be in your text message instead of the placeholders for variables such as %FirstName%, %OrgName% or %OptOut%.

Required Variables

As seen in the example above, there are required variables for inserting your Organization Display Name and Opt-Out Language. Please check out our guide Organization Display Name and Opt Out Language for more information

Remember that required variables count towards your character limit and impact the message segments. To make edits to these variables while crafting your initial message:

  • Click "Campaign Details" at the top of the page
  • Adjust the length of your required variables.
  • Click "Save" at the bottom of the page
  • Continue editing your script in the "Initial Message" step of campaign creation.

Monitoring Segment Usage

You can track the number of segments your organization has sent through various means:

  • Check your campaign and account-level exports.
    • Our Export Types article details which exports contain segment data and where to find that column in the csv.
  • View the "Segments Sent Per Month" in your Usage Analytics.
  • Quickly check your ThruText Dashboard to see this month's segment count.
  • If you're an admin on a primary account, you can also see your network's segments on the Subaccount Usage page.
  • Check the total amount of SMS segments sent on a campaign in the Analytics section of the Campaign's Details page. For an MMS campaign, add the initial sent & segments for the total segments on the campaign. 

Screenshot of a campaign's analytics in black text on a white background. Each set is separated by a light grey box. There is a green rectangle around the second number set, labeled "Segments".

Please send any questions or concerns to!