Writing concise SMS messages helps improve deliverability, reduce SMS costs, and create a better experience for your customers.
This guide explains how SMS messages are counted, when they're split into multiple billable segments, and why emojis or special characters can significantly increase the number of SMS segments your message uses.
Understanding SMS Segments
SMS messages are billed and delivered in segments, not as a single message.
The number of characters that fit into each segment depends on the type of characters used in your message.
Encoding | Single Segment | Concatenated Segment | Homeworks Maximum |
GSM-7 (standard English characters) | 160 characters | 153 characters | 10 segments |
Unicode (UCS-2) | 70 characters | 67 characters | 10 segments |
When a message is longer than a single SMS segment, additional segments include hidden data that allows mobile carriers to reassemble the message. This reduces the number of usable characters per segment.
❗️Homeworks allows a maximum of 10 SMS segments per outbound message.
What Causes a Message to Use Unicode?
If your message contains any character that isn't part of the standard GSM-7 character set, the entire message is sent using Unicode (UCS-2) encoding.
Unicode messages can contain fewer characters per SMS segment, so even a single special character may significantly increase your SMS usage.
Common Unicode characters include:
Emojis 😊 😂 ❤️ 👍
Smart (curly) quotes: “ ” ‘ ’
Em dashes: —
En dashes: –
Ellipses: …
Bullet points: •
Trademark symbols: ™ ® ©
Many accented letters
Non-breaking spaces
Apps like Microsoft Word, Google Docs, or Apple Pages automatically swap in the fancy curved version of an apostrophe, which SMS treats as a special Unicode character. When that happens, the entire message switches to a different encoding (UCS-2 instead of GSM-7), which cuts the characters-per-segment from 160 down to 70 and multiplies your segment count.
Before pasting text into the SMS editor, strip the formatting first.
On a Mac:
Open TextEdit, then go to Format → Make Plain Text before pasting. Or paste into the Notes app, then copy it back out.
On a PC:
Paste into Notepad (not Word) — Notepad strips all formatting and gives you clean plain text.
Quickest option on either:
Paste your text into your browser's address bar, then copy it back out. That strips everything instantly.
Once you're working with plain text, the apostrophes will be straight (') and your segment count should match what you'd expect.
Note: These characters are commonly introduced when copying text from Microsoft Word, Google Docs, Apple Notes, Outlook, or websites.
Example: One Character Can Change Everything
This message uses only GSM-7 characters:
Don't forget your appointment tomorrow at 2:00 PM.
This message contains a curly apostrophe:
Don’t forget your appointment tomorrow at 2:00 PM.
Although they look nearly identical, the second message is encoded as Unicode because of the single curly apostrophe.
That reduces the available characters per segment from 153 to 67 once the message spans multiple segments.
SMS Character Limits
Homeworks supports outbound SMS messages that are:
At least 1 character
No more than 10 SMS segments
Depending on the characters used, you'll reach the 10-segment limit at different message lengths.
Standard GSM-7 Messages
Messages using only standard GSM-7 characters can contain approximately 1,530 characters before reaching the 10-segment limit.
Unicode Messages
Messages containing Unicode characters can contain approximately 670 characters before reaching the 10-segment limit.
Important: If your message exceeds the 10-segment limit, it won't be sent until it's shortened.
Message Delivery Order
When a message spans multiple SMS segments, mobile carriers are responsible for reassembling those segments before displaying them to the recipient.
Important: Carriers don't guarantee that segmented messages will arrive in the order they were sent.
For the best customer experience, keep important information within a single SMS segment whenever possible.
Best Practices for Reducing SMS Usage
To reduce SMS usage and improve deliverability:
Keep messages under 160 characters whenever possible.
Avoid unnecessary emojis.
Replace smart punctuation with standard keyboard characters.
Replace:
“ ” with "
‘ ’ with '
— with -
… with ...
Avoid copying and pasting directly from Microsoft Word, Google Docs, Outlook, or websites.
Keep messages concise and focused.
Put the most important information at the beginning of your message.
Include one clear call to action.
Example: Replacing a single curly apostrophe with a standard apostrophe may keep your message in GSM-7 encoding and dramatically reduce the number of SMS segments used.
Known SMS Limitations
A Homeworks SMS Number Cannot Text Itself
A Homeworks SMS number can't send messages to the same phone number it is assigned to.
For example, if a customer's mobile number is also configured as your company's Homeworks SMS number, that customer won't receive outbound SMS messages from your account.
Frequently Asked Questions
Why was my message billed as multiple SMS messages?
Why was my message billed as multiple SMS messages?
SMS messages are billed per segment.
Longer messages are automatically divided into multiple segments, and each segment counts toward your SMS usage.
If your message contains Unicode characters—such as emojis or smart punctuation—it may require more segments than expected.
Do emojis increase SMS usage?
Do emojis increase SMS usage?
Yes.
Any emoji causes the entire message to use Unicode encoding, reducing the number of characters that fit into each SMS segment.
Because of this, even a single emoji can significantly increase the number of billable SMS segments.
Why won't my message send?
Why won't my message send?
Homeworks allows a maximum of 10 SMS segments per outbound message.
If your message exceeds this limit, it won't be sent. This often happens when a long message contains Unicode characters such as emojis, smart quotes, or special symbols.
Try shortening your message or replacing special characters with standard keyboard characters.
What's the longest SMS message I can send?
What's the longest SMS message I can send?
The longest message you can send depends on the characters it contains.
GSM-7 messages: Approximately 1,530 characters (10 segments)
Unicode messages: Approximately 670 characters (10 segments)
Messages that exceed the 10-segment limit won't be sent.
How can I reduce my SMS usage?
How can I reduce my SMS usage?
The easiest ways to reduce SMS usage are:
Keep messages under 160 characters whenever possible.
Avoid unnecessary emojis.
Replace smart punctuation with standard keyboard characters.
Avoid pasting formatted text from documents or websites.
Keep messages short and focused.
These small changes can significantly reduce the number of SMS segments used while improving message delivery.
Learn More
For additional information about SMS encoding and segmentation, see Twilio's documentation: