Free tool from SMS.es
SMS Calculator and Character Counter
Check how many characters your SMS has, how many parts it will take up, and whether it uses GSM-7 or Unicode UCS-2 encoding before sending it.
Online Calculator
Real-time SMS character counter
Type your message and instantly check the detected encoding, SMS segments, characters used, and remaining space.
Standard GSM-7 SMS
An SMS using GSM-7 characters can be up to 160 characters long when sent as a plain text message.
Unicode SMS UCS-2
If the message contains emojis or characters not included in GSM-7, the standard limit is reduced to 70 characters per standard SMS.
GSM-7 Extension
Symbols such as €, ^, {, }, [, ], ~, |, and \ are part of the GSM-7 extension and take up two positions.
Concatenated SMS
When the text exceeds the limit for a single part, it is divided into several SMS parts with a technical concatenation header.
Message Analysis
Detailed Character Breakdown
Check which characters belong to basic GSM-7, which ones use the GSM-7 extension, and which ones force Unicode UCS-2.
Type a message to see the breakdown.
Unicode code point ( hex)
Type a message to view the code points.
Technical Reference
GSM-7, Unicode, and Special Characters
Check the legend and character tables to understand why the length of an SMS varies.
Analysis Legend
GSM-7 Basic Character Set
These characters usually keep the SMS in GSM-7 encoding.
GSM-7 Extension
These characters are still GSM-7 characters, but they take up two positions within the message.
Examples of emojis
Emojis typically trigger Unicode UCS-2 and reduce the available length per part.
Examples of Unicode characters
Some symbols, alphabets, and special characters are not part of GSM-7 and cause the SMS to use UCS-2.
SMS Length
Why Does the Length of an SMS Change?
The actual length of an SMS does not depend solely on the visible number of characters. It is also influenced by the encoding used and the type of characters included in the message.
GSM-7 Characters
The GSM-7 alphabet includes letters, numbers, and many common symbols. If the entire text consists of characters from this set, the SMS takes full advantage of the standard 160-character limit.
Extension characters
Some symbols are sent with an escape character. Therefore, even though they visually occupy a single character position, they technically take up two within the SMS.
Unicode and emojis
When a character that is not compatible with GSM-7 appears, the message switches to UCS-2. This reduces the available space and may increase the number of SMS segments.
Concatenated messages
If the text exceeds a certain length, the operator divides it into several SMS segments. Each segment reserves space for the technical information needed to reconstruct the message.
From calculation to submission
Optimize your SMS before sending it
Once you've finalized the text, you can send SMS campaigns, integrate SMS into your systems, or check rates with SMS.es.
Best Practices
Tips for Writing SMS Messages
Before launching a campaign, review the length and clarity of the text, as well as any characters that might increase the number of parts.
Clear message
Focus on one main idea and avoid unnecessary phrases.
Use emojis with care
Avoid them if you need to maximize the number of characters or control costs per unit.
Check symbols
Check for accents, special characters, and GSM-7 extension characters.
Short Links
Use short URLs when the goal is to drive traffic to a page.
Try it first
Check the final text before sending it to the entire database.
Segment Better
Tailor the message to your audience to improve engagement and conversion.
Optimize your SMS before sending it
Calculate message length, adjust content, and create more efficient SMS campaigns with SMS.es.