SMS messages have strict technical limits that determine how many characters fit into a single message and how many credits are used. These limits are defined by global SMS standards used by mobile networks worldwide.
Mobile Message follows these standards exactly. The way your message is split into parts and charged in credits is not something we control or customise.
Understanding how SMS parts and Unicode work will help you avoid surprises when sending longer messages or messages that include emojis or non-English characters.
What is an SMS part?
An SMS part is a single segment of an SMS message.
A standard SMS part contains up to 160 characters
If a message exceeds the limit, it is split into multiple parts
Each part uses one SMS credit
For example:
1 to 160 characters = 1 part = 1 credit
161 to 306 characters = 2 parts = 2 credits
307 to 459 characters = 3 parts = 3 credits
This applies to standard (non-Unicode) messages.
Why SMS messages have character limits
SMS is a legacy technology that predates modern messaging apps. It was designed to be lightweight and efficient so messages could be delivered reliably across all mobile networks.
The character limits are defined by international GSM standards and enforced by mobile carriers. Mobile Message cannot change these limits.
When a message exceeds the character limit, the SMS system automatically splits it into multiple linked parts so it appears as a single message on the recipient’s phone.
Standard SMS characters (GSM-7)
Standard SMS messages use the GSM-7 character set.
If your message only contains GSM-7 characters, you can use up to 160 characters per SMS part.
GSM-7 includes:
Uppercase and lowercase English letters (A–Z, a–z)
Numbers (0–9)
Common punctuation and symbols such as:
. , : ; ? !
( ) [ ] { }
/ \ @ # % & * + - =
Space characters
These characters allow the maximum possible character count per SMS part.
Characters that are not standard SMS (Unicode)
If your message contains even one character outside the GSM-7 set, the entire message is sent as Unicode.
Unicode is required for:
Emojis 🙂
Accented characters (é, ü, ñ)
Non-English alphabets
Symbols not included in GSM-7
Examples of Unicode characters:
Emojis (😊 🚀 ❤️)
Smart quotes (“ ” ‘ ’)
Accented letters (á, è, ö)
Currency symbols such as € or £
Languages such as:
Chinese
Japanese
Korean
Arabic
Hindi
Cyrillic (Russian)
Greek
Thai
Unicode SMS character limits
Unicode messages have a lower character limit per SMS part.
A single Unicode SMS part supports up to 70 characters
Multi-part Unicode messages support up to 67 characters per part
This reduction is due to how Unicode characters are encoded in SMS.
Examples:
1 to 70 characters = 1 part = 1 credit
71 to 134 characters = 2 parts = 2 credits
135 to 201 characters = 3 parts = 3 credits
Even one emoji or accented character will trigger Unicode encoding and reduce the character limit.
Emoji support
Mobile Message fully supports emojis.
You can include emojis in your messages and they will be delivered correctly to supported devices.
However, emojis always require Unicode encoding. This means:
Your message will have a lower character limit per part
Your message may use more credits than expected
If cost control is important, be mindful of emojis and special characters when composing messages.
Language support
Mobile Message supports all languages that SMS supports.
If a language can be delivered via standard SMS networks, it is supported on our platform. This includes right-to-left languages and complex scripts.
Language support does not change pricing, but it does affect character limits due to Unicode encoding.
How credits are used
Credits are consumed per SMS part, not per message.
One SMS part uses one credit
Multi-part messages use multiple credits
Unicode messages usually use more credits for the same visible message length
The Mobile Message platform automatically calculates parts and credits before sending so you can see the cost in advance.
Why Mobile Message does not change these limits
SMS character limits and encoding rules are:
Defined by global GSM standards
Enforced by mobile carriers
Required for compatibility across all networks and devices
Mobile Message applies these rules consistently to ensure messages are delivered reliably worldwide.
Tips to reduce SMS parts
If you want to minimise credit usage:
Avoid emojis unless they are necessary
Avoid accented characters if possible
Use straight quotes instead of smart quotes
Keep messages concise
Review the character and part counter before sending