What’s the Deal with SMS Character Limits?

As text messaging becomes an increasingly popular tool for businesses, there are more and more questions about how best to use it. In fact, one of the questions people often have when it comes to using text messaging for business is character limits.

So we’ve put together a list of all the most frequently-asked questions pertaining to SMS and character limits.

What is the Character Limit for a Text Message?

Text messages have a character limit of 160 characters. This is a limit to the number of characters — e.g. letters, numbers, spaces, punctuation, and other special characters — that can be included in an individual text message.

What Happens When a Text Messages Goes Over the Character Limit?

Fortunately, going over the 160-character limit doesn’t stop a text message from being sent; however, it’s possible that longer messages can be split into separate 160-character texts, depending on the carrier.

Modern smartphones are able to stitch the messages back together because of a feature called SMS concatenation, which exists solely to help users overcome the restrictions of SMS.

It works like this: When an SMS message contains more than 160 alphanumeric characters, the sending carrier splits the message into separate 160-character messages. Each of the split messages is given a User Data Header (UDH) indicator — which could look something like [1/3], [2/3], [3/3] at the beginning of each message — to tell the receiving device how to stitch the texts back together correctly.

Uplink is compatible with concatenation, provided that the receiving carrier utilizes UDH indicators. Since the majority of networks support SMS concatenation, it won’t be a problem for most Uplink users; however, users who are on the Sprint network — or who use mobile virtual network operators (MVNOs) on the Sprint network — may experience some difficulties with concatenation.

In particular, the Sprint network doesn’t assign UDH indicators to messages that are split for sending. As a result, recipients of messages from Sprint users may receive multiple 160-character messages instead of having those messages stitched back together.

The following are MVNOs that could potentially have issues with sending longer text messages: Boom Mobile, Boost Mobile, CellNUVO, Charge Mobile, Chit Chat Mobile, EcoMobile, Expo Mobile, good2Go Mobile, Google Fi, Infinium Wireless, Kajeet, Net10 Wireless, NetZero, Ready Mobile, Red Pocket Mobile, Republic Wireless, Straight Talk, Telcel America, Tello US, Tempo Telecom, TextNow, The People’s Operator USA, Ting, Twigby, Virgin Mobile USA, ZingPCS.

Do You Have Any Other Questions About SMS Character Limits or Text Messaging?

If you have other questions about SMS, MMS, or messaging in general, don’t hesitate to let us know. We will continue adding more questions and their corresponding answers to this list as we receive them.


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