SMS character limit, and how to write a business text
A single SMS holds 160 characters in the standard GSM-7 set and 70 when the message contains an emoji or another character outside it. Longer messages travel as linked parts of 153 or 67 characters, each charged as one message. Every commercial text must identify the sender and carry a working unsubscribe.
119 characters, 119 GSM-7 billing units, one SMS part.
41 GSM-7 units remain in the final SMS part.
All characters fit the GSM-7 character set.
1,000 sends cost $30.00 at Texto's 3.00c and $69.00 at the median 6.90c, using the published 1K benchmark rates per SMS part.
A single SMS holds 160 GSM-7 billing units or 70 in UCS-2. A longer message bills in parts of 153 or 67 units. Characters outside GSM-7 switch the whole message to UCS-2. Emoji can use several billing units; the count above shows how many this message uses. Rates exclude GST and any carrier surcharge.
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The SMS character limit
A single SMS holds 160 characters as long as every character belongs to the standard GSM-7 character set: plain letters, numbers and common punctuation. The moment you use any character outside that set, the whole message switches to UCS-2 encoding and a single SMS holds just 70 characters.
The usual culprits are emojis, many accented letters and curly quotation marks. One emoji can triple your message cost without you noticing. Use straight quotation marks and skip the emojis unless the shorter limit suits you.
A handful of GSM-7 characters count as two characters each: the euro sign, square brackets, curly braces, the backslash, the tilde, the caret and the vertical bar. They stay within GSM-7, but they eat into your 160 faster than you expect. Square brackets are common in placeholders, so count them carefully.
How long messages are split and charged
A message longer than one SMS is not rejected. The mobile networks send it as linked parts that join back together on the recipient's phone as one long text. Each part holds 153 characters in GSM-7 or 67 in UCS-2, because some space in every part carries the joining information.
Providers charge each part as one message. A 161-character GSM-7 message is one character over the single-SMS limit, so it goes as two parts and costs the same as two messages. The first part carries 153 of your characters and the second part carries the remaining 8.
This is why the limit matters for your budget as well as your wording. Trimming a message from 161 characters to 160 halves what you pay for it. Check the character counter in your provider's web app before you send.
What every business text must include
The Spam Act 2003 governs commercial text messages in Australia, and the ACMA enforces it. Every commercial message needs consent from the recipient, express or inferred, and you have to be able to show that consent. Sending without it is your risk, not your provider's.
The message must clearly identify who sent it and include accurate contact details for your business. It must also carry a functional unsubscribe that stays live for at least 30 days after sending and is honoured within 5 working days. A line such as "Reply STOP to opt out" is the common convention. The law requires a working unsubscribe, not that exact wording.
The obligations fall on you as the sender. Choosing a compliant provider does not move the duty onto them.
How the sender name affects your message
A branded sender ID shows your business name at the top of the text instead of a number. It runs from 2 to 11 characters. Since 1 July 2026, a sender ID must be registered on the ACMA SMS Sender ID Register through each SMS provider you send with.
Registration is open now. An unregistered sender ID is replaced with the word "Unverified" and the message is still delivered, which is not the look most businesses want.
A sender ID cannot receive replies. To take replies, you send from a number: a dedicated virtual mobile number, which carries a monthly fee on top of the message rate and stays the same across campaigns, or a shared number, usually included at no extra cost though the number can change. Ask for a reply only when you send from a number.
Writing the message
Give each message one purpose. A reminder reminds, a notice informs, an offer sells. Mixing purposes makes texts longer and blurs the action you want the reader to take.
Put the business name and the action first. The reader should see who sent the text and what to do before anything else.
Watch your characters when you want to stay within 160. Straight quotation marks, no emojis and plain punctuation keep you in GSM-7. Remember the characters that count as two, including square brackets.
Never put passwords, full card numbers or health details in a text. A standard SMS is not end-to-end encrypted.
Example messages
- "Harbour Physio: your appointment with Sam is on Tue 14 Oct at 10:30am. Reply R to confirm or call the clinic to change." (119 characters, one SMS)
- "Your parcel from Harbour Parcels is out for delivery today and should arrive between 10:30am and 1:30pm." (104 characters, one SMS)
- "Harbour Physio here. Book your next session online before Fri 31 Oct and pick a time that suits. Reply STOP to opt out." (119 characters, one SMS)
Frequently asked questions
What is the character limit for an SMS?
The character limit for an SMS is 160 characters when every character is in the standard GSM-7 set. That covers plain letters, numbers and common punctuation. A few GSM-7 characters count as two, including square brackets and the backslash, so a text of 158 symbols can still exceed the limit. Longer messages go out as linked parts.
Do emojis change the SMS character limit?
Emojis do change the SMS character limit. One emoji switches the whole message from GSM-7 to UCS-2 encoding, where a single SMS holds 70 characters instead of 160. Parts of a long UCS-2 message hold 67 characters each. Other common triggers include curly quotation marks and many accented letters, so plain punctuation is the safer habit.
How are long text messages charged?
Long text messages are charged by the part. A message beyond one SMS travels as linked parts holding 153 characters each in GSM-7, or 67 in UCS-2, and your provider counts each part as one message. A 161-character GSM-7 text costs the same as two messages, so trimming one character can halve the charge for that send.
What must a marketing text message include?
A marketing text message must include clear identification of your business with accurate contact details, plus a functional unsubscribe that stays live for at least 30 days and is honoured within 5 working days. A line such as "Reply STOP to opt out" is the common form. Under the Spam Act the duty sits with you as the sender, not your provider.