SMS Character Limit
A standard SMS is 160 characters. Go over and it splits into multiple messages — and you might get charged per segment. Here is what you need to know.
| Encoding | Single SMS | Per segment (multi) | Triggered by |
|---|---|---|---|
| GSM-7 | 160 chars | 153 chars | Standard Latin text |
| UCS-2 / Unicode | 70 chars | 67 chars | Any emoji, accented or special chars |
Why 160 characters?
The 160-character limit was set in 1985 by Friedhelm Hillebrand at Deutsche Telekom. He analysed postcards and telex messages and concluded that the vast majority of meaningful short communications fit within 160 characters. This limit was built into the GSM standard and has remained unchanged for 40 years — long after the constraints that originally influenced it have disappeared.
What happens when you go over 160 characters
Your device automatically splits the message into multiple segments. Each segment beyond the first reserves 7 characters for a User Data Header (UDH) that tells the recipient's device how to reassemble the parts. This reduces usable characters per segment from 160 to 153.
A 161-character message = 2 segments = 2 SMS charges. A 307-character message = 2 segments (153+154). A 308-character message = 3 segments. If you're sending bulk SMS for marketing, every extra segment multiplies your cost.
Emoji cut the limit to 70 characters
Adding any emoji — or any character outside the GSM-7 character set — forces the entire message into Unicode (UCS-2) encoding. UCS-2 uses 16 bits per character instead of 7, halving the capacity. A message with a single emoji has a single-SMS limit of 70 characters and a per-segment limit of 67 characters for multi-part messages.
The same applies to curly/smart quotes (“ ” ‘ ’), en dashes (–), ellipsis (…) and accented characters like é, ü, or ñ. If your text editor auto-corrects straight quotes to curly quotes, the resulting SMS will be Unicode-encoded.
Checking your SMS character count
Use the Character Counter to see your exact character count before sending. The SMS character limit row in the platform limits section shows how many characters you have remaining in a single SMS and turns red when you go over 160.
Count your SMS characters now
Paste your message and see instantly if it fits in one SMS or splits into multiple.
Use Character Counter →Frequently asked questions
What is the SMS character limit?
A single SMS message is limited to 160 characters when using the standard GSM-7 character encoding. If your message exceeds 160 characters, it is automatically split into multiple parts, each carrying a 7-character header for reassembly — reducing each segment to 153 usable characters. A 161-character message becomes two segments using 153 + 8 characters.
Why is the SMS limit 160 characters?
The 160-character limit was set in 1985 by Friedhelm Hillebrand and Bernard Ghillebaert at Deutsche Telekom. Hillebrand analysed postcards and telex messages and found that most everyday communications fit within 160 characters. This limit was then built into the GSM standard. It was a deliberate design decision, not a technical constraint.
What happens when I send a text over 160 characters?
Your phone automatically concatenates the message — splitting it into multiple SMS segments. Each segment beyond the first uses 153 characters (7 characters are used for a User Data Header that tells the recipient's phone how to reassemble the parts). You may be charged per segment by your carrier. Most modern smartphones display the reassembled message as one, but older phones may show separate messages.
Does using emoji reduce the SMS character limit?
Yes, significantly. Emoji are encoded in Unicode (UCS-2), not GSM-7. When you include any Unicode character or emoji, the entire message switches to UCS-2 encoding — which uses 16 bits per character instead of 7 bits. This reduces the single-message limit from 160 to 70 characters, and multi-part segments from 153 to 67 characters.
Do special characters affect the SMS character limit?
Yes. The standard GSM-7 character set includes basic Latin letters, numbers and common punctuation. Characters outside this set — including many accented characters, curly quotes, en dashes, and any Unicode character — trigger UCS-2 encoding, cutting the per-message limit from 160 to 70 characters. Always check your SMS character count with a tool before sending marketing messages.
What is the character limit for WhatsApp and iMessage?
WhatsApp allows up to 65,536 characters per message. iMessage (when sent as a blue bubble) does not have a documented character limit but allows very long messages. Neither uses SMS segments — they transmit over the internet. The 160-character limit only applies to traditional SMS (green bubble on iPhone, or any text sent without internet).