Overview

Do you know that SMS has a 98% open rate compared to email marketing?

Even though SMS may seem incredibly clunky and basic, it often yields powerful results.

However, it is widely understood that SMS has a limited character count. How long can a text message be? What is the upper limit on the length of a text message? This guide will reveal all.

What is the SMS character limit?

A standard SMS length has a limit of 160 characters. Nevertheless, many modern phones and networks support concatenation; they segment and rebuild messages up to 1600 characters. If you use unique characters or UCS-2 (i.e., for Thai, Arabic, Chinese, and Japanese), it will decrease to 70 characters.

SMS message length and character encoding

When you send an SMS message over 16 characters, the message will be split. Large messages are segmented into 153 character segments and sent individually, then rebuilt by the recipient's device. For instance, a 161-character message will be sent as two messages, one with 153 characters and the second with 8 characters.

If you include non-GSM characters, such as Chinese script, in SMS messages, those messages have to be sent via UCS-2 coding. Messages including any UCS-2 characters are limited to 70 characters and will be concatenated into 67 character message segments, even if the messages contain fewer than 160 characters.

What is the history behind SMS message length?
SMS is a standardized communication protocol that enables devices to exchange short text messages and was defined as part of the 1985 GSM protocol. At first, it was built to "fit in between" existing signalling protocols, which is why the SMS length is limited to 160 seven-bit characters. It was subsequently codified into the SMPP signalling protocol, which transmits SMS and is limited to precisely 140 bytes (or 1120 bits).

However, things get tricky because GSM-7, the original character set designed for SMS, only has the ability to denote 128 different characters in those 7 bits. Therefore, if you want to include more Latin or non-Latin scripts, you will need to use UCS-2.

A common mistake is to inadvertently use a UCS-2 character, thinking it is GSM-7 character. GSM-7 is not a supported character set in many text editors. The classis mistake is to use "curly quotes" not realizing that they are part of UCS-2 and not GSM-7.

What is the maximum character count for an MMS message?

Sometimes, words alone won't cut it. With MMS (Multimedia Messaging Service), you're able to send photos, videos, and GIFs to your subscribers. Each MMS Message can include up to 1,600 characters.

What counts as a character in a text message?

Any standard letter, symbol, or space counts as a single character. The exception to that rule is the newly popular and highly effective emoji. These symbols often take up two characters. Emojis can help drive a message home and create a relatable repertoire between you and your reader, but they should be sparingly used in order to not eat up your 160 characters all at once.

Does sending a longer message cost more?

Yes, it does.

The longer the text, the more credits will be used to send the message. The first 160 characters will use one text credit, the subsequent blocks 153 characters will use additional credits. The 7 character difference is used as code to allow the messages to arrive as one text, rather than a series of individual messages.

Don't know how to start with SMS? Head to our guide on Getting Started with SMS/MMS in AVADA for more information.
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