For each text message, there is a 160 character limit. If you send one text message that is 160 characters or less, you will be charged only one credit for that message.
Note that character count is how many letters, numbers, spaces, and line breaks are in your message. Once the character count goes over 160 characters, additional credits will be used. (For example, 180 characters count as two credits)
(NOTE- In Canada, the limit is 140 characters per credit)
Some people are confused as to why when they send a message, they see a 450 limit (view picture)
The "limited to 450" message above is the final number of characters that can be sent for messages. So a 450 limited message would amount to 3 text messages (160+160+130=450), resulting in 3 credits.