The amount of credits you will spend depends on the country of the recipients, the number of SMS and the number of characters you send. Here is the table of prices. If a country has a sender, it means that the sms will be sent as "Odoo". It is possible to register your own sender in your IAP account setting (soon):

The limit size of an SMS depends on the type of the SMS.
For a standard message, the size limit is 160 characters.
For a unicode message, the limit is set to 70 characters.

When an SMS is longer than theses limits, the SMS is considered as a multi-part message.
The SMS will be sent in multiple parts, and rebuild by the end user's device, in order to show it in one message. So, to allow the end user's device to rebuild correctly the SMS, the limit is reduced to 153 characters and 67 characters. The remaining characters contains the information on the way to rebuild theses parts.

A SMS message can be either a standard message or a unicode message.

• Standard Message (GSM7): SMS which contains only characters from the GSM-7 set (see below).
• Unicode Message (UNICODE): SMS which contains at least one character that isn't in the GSM-7 set.

The GSM-7 set is a set of characters that can be used in a standard SMS.

Please note that carriage return (Enter) counts as 2 characters.

Some countries allow the sender of the sms to display a name to identify itself. This name is called the sender name.
The sender name is limited to 11 characters and can only contain letters and numbers.
You can set it in the options tab of your sms account. Be careful however, the sender name can not be changed by after. If you need to change it, please contact our support.

When the country supports it, your sender name will be used. Please note however that in some countries, the sender is not displayed, or is forced to "Odoo".
You can see which sender will be used in the first question of this FAQ.
If you don't set any sender name, the number will be printed instead.