Sending a message that exceeds industry-standard character limits will result in it being split into multiple parts. Each part is billed as a separate SMS, which will increase the total cost of sending the message. This article explains how to keep your messaging costs predictable by understanding these limits.
How message length affects your invoice
To avoid surprises on your invoice, it's crucial to understand how message length impacts your costs.
In short, longer messages cost more.
Here’s why:
- Messages Have a Limit: The mobile industry sets a standard character limit for a single SMS message. This is not a Sinch rule, but a standard that all providers must follow.
- Splitting Long Messages: If your message goes over this limit, it is automatically split into multiple, smaller message parts that are used for billing calculations. However, it will still appear as a single, complete message on the recipient's phone.
- Billing Per Part: Each of these individual parts is treated as a separate SMS. This means each part will use one of your credits and will be billed as a distinct message on your invoice.
Example:
If you send one long message that gets split into three parts, you will see it as three separate charges on your bill and it will consume three credits.
Being mindful of message length when you write your campaigns is the best way to manage your budget and prevent unexpected charges.
Message character limit breakdowns
Messages containing only standard (GSM) characters: 160 characters
- After 160 characters your message will become multi-part with a limit of 153 characters per part.
- When your message is split into multiple parts, some characters get used up by invisible headers and footers, which are used to identify which part of the message is being sent (e.g. Part 1 of 2).
Messages containing special (Unicode) characters: 70 characters
- After 70 characters your message will become multi-part with a limit of 67 characters per part.
- These limits will apply to any message containing special characters, even if there are standard characters present as well.
| No. of Messages (billing units) | Standard Characters | Unicode Characters |
| 1 | 1 – 160 | 1 – 70 |
| 2 | 161 – 306 | 71 – 134 |
| 3 | 307 – 459 | 135 – 201 |
| 4 | 460 – 612 | 202 – 268 |
| 5 | 613 – 765 | 269 – 335 |
| 6 | 766 – 918 | 336 – 402 |
| 7 | 919 – 1071 | 403 – 469 |
| 8 | 1072 – 1224 | 470 – 536 |
Monitoring character limits
The message composer provides some information about your content such as the number of characters and how many SMS (billing units) this equates to per contact. It will also display warnings if there are special characters or emojis in the content that may result in additional charges.
Smart encoding
When copying and pasting message content from an external source like a Word document, it's possible your message might contain Unicode characters without it being obvious, particularly if you've copied across any paragraph formatting like "tab" or "whitespace" characters.
In the Sinch MessageMedia platform, Smart Encoding can identify common accidental unicode characters and replace them with their equivalent GSM character, ensuring the message goes out as GSM and not inadvertently triggering a 70-character limit on the whole message.
A full table of replacements is attached at the bottom of this article.
If you want Smart Encoding to be turned on for your Hub account, reach out to our Support Team.
Sending emojis
- Provided that the recipient network supports emojis, you can add them to your messages. If the recipient network doesn't support emojis, they'll be stripped out.
- Using emoji changes the message to Unicode - they're counted as 2 Unicode characters each.
- Emojis can be copied and pasted into the message content field from an external source, or via the emoji button if you're writing your message from the inbox.
- This webpage includes a table of emojis that can be copied and pasted into your messages.
For more information on character limits in SMS messages, check out this Blog post