The SMS standard has defined an SMS segment as any block of text that includes up to 160 base characters. If the message includes any character outside of the base (GSM) character set, the maximum number of characters included in each segment will be less than 160 character. To see the characters included in the GSM (base) character set, please visit: https://en.wikipedia.org/wiki/GSM_03.38

As you review the GSM character set, you’ll want to note that the apostrophe symbol is part of the GSM character set, but the single open quote symbol (mistakenly used as an apostrophe at times) is not. For many users, it is common practice to use a word-editing application like Microsoft Word to construct and finalize SMS messages before sending to patrons. If you happen to construct your SMS messages in this manner, be informed that some word-editing applications may inadvertently use a single open quote in place of an apostrophe, thus reducing the number of characters you’re able to send in an SMS segment. As an extra precaution, you may wish to use the following tool when constructing your SMS messages to test if your SMS message will be split into multiple segments based on number of characters and character encoding: http://chadselph.github.io/smssplit/

Once you’ve pulled up the tool and you’ve entered in your message into the “How Messages Get Split” open field, there are three options to select. The “Auto” option shows how your message is represented in segments with nothing changed. The “GSM” option shows all base characters in black font and other characters outside of the GSM character set in red font so you can see what character may cause message splitting. The “USC2” option shows the message split into segments based on character length and encoding.

Ideally, you want to stick to the GSM characters to maximize the number of characters per segment. This will provide you with two benefits:

  1. Your messages are delivered at a faster rate (the less segments per message, the less messages have to be broken up and pieced back together when transmitting them to recipients).
  2. It’s more cost-effective for you by helping you keep within your SMS message limit associated with your SMS subscription.

Thank you for your attention to this important update.

Mike Hilmo


Chris added - from personal experience I know some cheap track phone/pay as you go services will NOT receive any part of message that is over the 160 characters that gets split.