In Notify Me, SMS messages are billed based on segments, not per message.
A single SMS message may use multiple segments depending on its length and character type.
This means a longer message or one that includes special characters or emojis may count as 2, 3, or more segments - and you'll be billed accordingly.
What’s an SMS Segment?
An SMS segment is a portion of your message that fits within a specific character limit:
GSM-7 characters (standard English letters): 1 segment = 160 characters
Unicode characters (emojis, accents, non-Latin scripts): 1 segment = 70 characters
When your message exceeds these limits, it’s split into multiple segments, and each one is billed separately.
For example:
A 300-character English message = 2 segments
A 160-character message in Arabic = 3 segments
For more information on how GSM-7 encoding works and its technicalities, you can refer to the Twilio Glossary on GSM-7 Character Encoding.
How Segment Count Affects Your Charges
You’re billed per segment based on the destination country. If you see “250 segments of SMS” on your bill, that means the total cost is calculated as:
250 segments × [price per segment for that country]
Prices vary by country and are listed in your billing settings.
Why Your Segment Count May Seem High
A few reasons you might be using more segments than expected:
Your message includes dynamic fields like
{{product_name}}or{{shop_name}}- longer values increase character count.The message is written in Unicode-based languages (like Arabic, Chinese, etc.)
You're including emojis, symbols, or special punctuation.
Some fields (like unsubscribe instructions) are appended automatically and count toward the total.
To understand more about how dynamic fields, Unicode characters, and special characters affect segmenting, check out our article on How SMS Segments Are Calculated.
Example Calculation
You wrote this template:
"{{product_name}} is back in stock at {{shop_name}}. Buy it now before it goes out of stock again! {{product_url}}"
Sending a back in stock SMS for a sample product:
Nike Running Shoes is back in stock at RunWorld. Buy it now before it goes out of stock again! https://abc.runworld.com/123
To unsubscribe reply 1
Product name: Nike Running Shoes (18 characters)
Shop name: RunWorld (8 characters)
Product link: https://abc.runworld.com/123 (28 characters)
Plus unsubscribe text: To unsubscribe reply 1 (22 characters)
Rest of the text (69 characters)
Total estimated characters: 145 characters
GSM-7 encoding: 1 segment (since the message is under the 160-character limit)
If you add any emoji or special character, this will result into a 3 segment Unicode system.
How to Stay Within 1 Segment
Keep your message short and simple
Avoid emojis or special characters
Use abbreviations where appropriate