SMS character limit: how many characters fit, which ones count double and how to save on your sends
Why a single accent can turn one message into two, and how to avoid it
An SMS allows up to 160 characters if it uses the basic GSM-7 alphabet. If it includes a character outside that alphabet, such as an emoji or á, the limit drops to 70. If the text goes over that limit, it is split into several SMS and each part is charged separately.
It looks like a technical detail, but it affects what you pay for every SMS marketing campaign. A single “ó” can turn a 150-character message into two SMS.
How many characters can an SMS have?
The number of characters in an SMS depends on the message’s encoding: the character set the phone uses to send it. There are two:
| Encoding | When it’s used | Characters in 1 SMS | Characters per part if split |
|---|---|---|---|
| GSM-7 | Only letters, numbers and symbols from the basic alphabet | 160 | 153 |
| Unicode (UCS-2) | There is at least one character outside the basic alphabet | 70 | 67 |
The rule is all or nothing. A single Unicode character is enough to switch the whole message to Unicode and drop the SMS character limit from 160 to 70.
Why does a long SMS have 153 characters per part?
When a text goes over the limit, the carrier sends it as several SMS and the recipient’s phone puts them back together. So the phone knows how to join them, each part carries an invisible header that takes up space.
That’s why each part loses 7 characters in GSM-7 (from 160 to 153) and 3 in Unicode (from 70 to 67). Here’s what that means in practice:
| Text length (GSM-7) | SMS charged |
|---|---|
| Up to 160 characters | 1 |
| 161 to 306 | 2 |
| 307 to 459 | 3 |
| 460 to 612 | 4 |
In Unicode, the jumps come sooner: at 70, 134, 201 and 268 characters.
Which characters drop an SMS to 70?
The GSM-7 alphabet includes unaccented letters, numbers and the most common punctuation marks. It also includes some Spanish letters, such as ñ, é, ü and the ¿ and ¡ marks.
But not all of them.
These are the characters that most often switch an SMS written in Spanish to Unicode:
- Accented vowels: á, í, ó, ú and their capitals (Á, É, Í, Ó, Ú). Lowercase é is GSM-7, though.
- Emojis of any kind. Many take up two of the 70 positions.
- Typographic quotation marks («», “”) and the curly apostrophe (’). The straight double quote (“) and the straight apostrophe (‘) are GSM-7.
- Em dashes (—) and the single-character ellipsis (…).
- Lowercase ç and letters from other languages, such as ã or õ.
Many of them sneak in when you copy text from Word or a website. Always check the message in the editor before sending it.
Characters that count double in an SMS
Some symbols do belong to GSM-7, but take up two positions because they are preceded by an invisible escape character. These are:
| Character | Name | Counts as |
|---|---|---|
| € | Euro sign | 2 |
| [ ] | Square brackets | 2 each |
| { } | Curly braces | 2 each |
| \ | Backslash | 2 |
| | | Vertical bar | 2 |
| ^ | Caret | 2 |
| ~ | Tilde | 2 |
The most common case is the euro sign. “From €9.99” takes up 11 positions, even though it has 10 characters.
Send SMS with no surprises on your bill
The Mailrelay editor counts characters in real time and warns you if the message will be charged as several SMS.
How to write an SMS without going over the character limit
With a few tweaks you can keep the message to a single SMS:
- Choose words without accents when you can: in Spanish, “envío” can be replaced with “pedido” or “paquete”, and “está en camino” with “va de camino”.
- Use link shorteners. A long URL can take up half the message, and it’s even better if it leads to a mobile-friendly landing page.
- Swap typographic quotation marks and dashes for straight ones (” and -).
- Save emojis for short messages, where you have room to spare even with the 70-character limit.
- Count the opt-out too: the sender name doesn’t take characters away from the message, but the unsubscribe instruction does.
Don’t strip out accents if it hurts your brand image. Sometimes it’s worth paying for two SMS so the text reads well.
Example: the same SMS in GSM-7 and in Unicode
See how the character count of a shipping notification transactional SMS changes with just a few letters:
Unicode version (70 characters per SMS): “Tu pedido está en camino. Llegará mañana entre 9 y 14 h. Síguelo aquí: tutienda.es/envio”
GSM-7 version (160 characters per SMS): “Tu pedido ya va de camino. Te llega mañana entre 9 y 14 h. Puedes seguirlo en: tutienda.es/envio”
The first text has 88 characters and is charged as 2 SMS, because the accents in “está”, “Llegará”, “Síguelo” and “aquí” switch it to Unicode. The second has 96 and is charged as 1 SMS, because “ñ” is part of the GSM-7 alphabet.
How to keep track of your SMS characters with Mailrelay
With Mailrelay you can send mass SMS from the same account you use for email marketing, and send SMS from your computer without installing anything.
The editor has a character counter. It warns you in real time if the text goes over 160 characters, or 70 with emojis or special characters, and will be charged as several SMS.
You can personalize each message with the contact’s name and use an alphanumeric sender with your company name. The cost per country is listed in the SMS pricing, and credits come with no long-term commitment.
Email and SMS from a single account
Send your mass SMS with a custom sender and no long-term commitment, alongside your email campaigns. Start for free.
Frequently asked questions about SMS characters
These are the most common questions when writing an SMS.
How many characters can an SMS have?
160 characters if the text only uses the GSM-7 alphabet, and 70 if it includes any emoji, accented vowel (except é) or other special character.
Do spaces count as characters in an SMS?
Yes. Spaces, line breaks and punctuation marks count the same as a letter in an SMS.
Does ñ count as a special character in an SMS?
No. ñ and Ñ are part of the GSM-7 alphabet, so they don’t lower the limit to 70.
What happens if an SMS has more than 160 characters?
It is split into parts of 153 characters that the phone joins when it receives them (67 if the text is in Unicode). The recipient reads it as a single message, but it is charged as several SMS.
What is the difference between an SMS and an MMS?
SMS only supports text and has a character limit. MMS lets you send images, audio or video, and it costs more. For more details, see what is an SMS.