A Standard SMS has a capacity of 160 characters only from the GSM alphabet.
In the case that characters not present in the GSM alphabet (accents, emoticons, symbols, etc.) are included, it is necessary to send Unicode SMS with a capacity of 70 characters.
It is possible to send Standard or Unicode concatenated SMS but each part or segment will have a unit cost according to the country of destination.
More information about Types of SMS messages or What is the price of an SMS message?.