How are SMS costs calculated?
When you use Clubworx to build SMS templates and send SMS messages, you may notice text under the message content field that shows:
Your message's character count;
The number of message parts this resolves to; and
The maximum number of characters remaining.
Each month, your account will be charged based on your per-SMS fee and the total number of message parts that were successfully sent that month.
So if you have a per-SMS fee of $0.10 and you sent 10 messages that contained 25 message parts, your total SMS fee would be $2.50.
How are message parts calculated?
The two factors that decide how many parts a message contains are:
The length of the message (number of characters); and
Whether it contains any Unicode characters (incl. emojis, as well as other non-standard characters that are not in the GSM-7 character set).
If the message does NOT contain any Unicode or non-standard characters, message parts will be calculated using the following rule:
If the message is 160 characters or less (including the "reply STOP to unsub" message that is applied automatically to some messages), then the message contains only 1 billable part.
If the message (including the "reply STOP to unsub" suffix) is 160 characters or longer, then the message will be broken up into parts of 153 characters.
Note: the recipient may or may not notice that the message has been broken up. This will depend on factors like the recipient's device and phone provider.
So, if a message is between 161 and 306 characters long it will be contain 2 billable parts; if it is between 307 and 459 characters long it will contain 3 billable parts, and so on.
However, if the message contains one or more Unicode (or non-GSM-7) characters, the following rules will be applied instead:
If the message is 70 characters or less (including the "reply STOP to unsub" message), then the message contains only 1 billable part.
If the message (including the "reply STOP to unsub" suffix) is 70 characters or longer, then the message will be broken up into parts of 67 characters.
These alternate rules are applied because Unicode characters require the message to be sent in a different format that takes up more space per-character.
How can I minimize SMS costs?
Since using Unicode reduces the maximum length of your message parts, you'll probably want to avoid using it where it's not needed.
For this reason, Clubworx will automatically convert many Unicode characters to their non-Unicode equivalent when sending SMSes, to give your messages the best possible chance of being Unicode-free.
For example, if your message contains smart quotes (“ or ”), we will automatically replace these with the non-Unicode quote character (").
One place where we cannot automatically replace Unicode for you though is when your message contains emojis. Any messages containing emojis will have to be sent using the more strict Unicode message lengths, and so those messages are likely to attract higher costs. This means a quick and easy way to minimize SMS costs can be to limit emoji use when sending SMSes.
More information
If you need more information on any of these points, contact our support team today.