SMS Cost Calculations

Segments

An SMS comprises segments and each segment is 160 characters long. So if you are sending a lengthy SMS, it will consume multiple segments and thereby drive up your cost.

Please note that while 160 characters form a segment, even using 161 characters counts as 2 segments.
Character lengths of segments also vary by countries & regions which might affect your SMS costs.

Having hidden characters in your SMS text

Many people copy/paste the SMS text body while designing automation. When you copy/paste text from a text editor software like MS Word or Google Docs, sometimes hidden characters get appended in the string. These hidden characters can not be seen by the user but they are present in the text.

Example

In this example a simple phrase Hey there was copied from a webpage. Usually, it should be just 1 segment. But actually, it contains many hidden characters (empty characters) making this as large as 4 segments.

You can use https://twiliodeved.github.io/message-segment-calculator/ to check the actual number of segments & character length of your SMS text.
While pasting contents of an SMS to System text editor it is recommended to use paste as plain text option instead of simple paste.

Using Emojis

This is the most common reason for unexpected high costs while sending SMS automation.

If you use emojis you could increase the number of segments from 1 to 4.
Using emojis is a great way to make your automation exciting but being aware of the costs involved will help you make an informed decision about their frequency of usage.

Using a picture attachment

Both SMS and MMS carrier fees will apply which could drive up the cost of each SMS. When you send a picture message with text, you get charged $0.02 for the picture + the usual SMS cost depending upon the length of the text.

Carrier fees

Further, there might be some additional charges incurred: