SMS content and length

How long can an SMS message be?

It depends on message content. If the message contains only characters specified in the so-called GSM alphabet - Latin uppercase and lowercase letters, numbers common punctuation and some diacritics, an SMS message can have up to 160 characters (several characters like the euro symbol €, square and curly brackets - [ ] { }, tilde ~, backslash \, caret ^ and vertical bar | take up two spots so each use of these characters will decrease the remaining characters by 2.

This is usually enough for messages in languages like English or even Finnish where the additional diacritics are still covered by the GSM alphabet.

If, and as often is the case, these characters are not enough, Unicode encoding is employed which allows use of almost any character at the expense of decreasing the possible message length to 70 characters.

What about longer messages?

Indeed, longer messages are possible and are often used. This is done with so-called long or concatenated SMS messages which, behind the scenes, are simply several ordinary messages with indication of how the phone should assemble them to appear seamlessly to the user as one long message. However, accommodating this indicator has some impact on message length: the length for each part in a GSM alphabes message is just 153 characters as apposed to 160, and in. Unicode encoding - 67 instead of 70. So, fo example, a 3 part message can be up to 459 or 201 characters long, respectively.

These long messages are counted towards your balance as the number of SMS parts they consist of, so, for example, a 200 character message in the GSM alphabet will be counted as 2 SMS in your account.

Updated on: 08/12/2020