Why data fields might increase SMS cost

Learn why adding personalisation data fields to your SMS messages might increase the cost of your sends.


Adding personalisation to your SMS messages is a great way to communicate directly with your customers – in fact, due to the personal nature of SMS, most users expect a higher level of personalisation. But before you go using your data fields, it's essential to be aware of how personalisation can increase the overall message length and cost of your SMS sends.

How data fields affect SMS length and cost

If you're using data fields to store personalisation attributes for your contacts, then every data field might be a different length. At first, this might not seem like a problem until you start looking at how this can affect message length and cost.

One SMS message segment has a maximum character count of 160 characters. Every time the character count of the SMS message is more than 160 characters, it is sent and charged as two SMS message segments – these segments are combined and appear as one message on your customer’s phone but they are still billed individually.

Additional segments vary in their maximum character count. To learn more about the character count of SMS segments, check out our article on Long SMS messages.



You've written a 155-character SMS message to send to your contacts. You've started the message with some personalisation by using data field 1 – this is your contact's first name. On the message preview; it looks like this:

Hey, @field1@.

At this point, we can't give you an accurate character count for your message, because the character count is different for every contact depending on the length of their first name.

To keep things simple, imagine you only have two contacts in your address book: Amar and Charlotte. Because Charlotte has over double the number of characters in her name, the SMS message to her has more characters. The breakdown below demonstrates how the character count, message count, and overall billing cost is affected by the personalisation added to these two SMS messages.

  SMS to Amar SMS to Charlotte
Message length: 159 164
Maximum characters per message: 160 160
Calculation: Original message (155) + Amar (4) Original message (155) + Charlotte (9)
Total messages sent: 1 2
Total messages sent: 1 2

To sum up

Don't avoid using personalisation, but be aware of the possible additional cost when adding data fields.

If you do use personalisation, keep messages short and know the maximum length of the data fields you're adding. If you can't keep it short, be happy that although it may cost more, adding the personal touch can make your message more effective.

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