7-bit encoding

This is the most commonly used encoding for messages with GSM 03.38 character set. In this 7-bit alphabet you can use only following characters:

There are also some characters in the GSM 03.38 Extension Table that can be used for the cost of two characters by prepending escape character ESC (0x1B):

The message length for 7bit encoding is up to 160 characters.

Unicode Encoding

Unicode (UCS-2) encoding supports a great range of characters and languages compared to the very limited alphabet of 7bit encoding.

If your message contains any characters not listed in the 7-bit alphabet, UCS-2 encoding is automatically used. In this case, each message takes up a lot more space, thus the message length is reduced to 70 characters.

Multipart SMS messages

When the message length sent through an SMS API , for example, exceeds the SMS character limit of 160 characters in case of 7bit encoding (or 70 characters for UCS-2 encoding), the message is split up into multiple separate SMS and sent to the handset separately as well. So, it's important to use this calculator to make sure that you don't exceed the limit and pay more than you planned.

To be able to concentrate the messages on the phone, a special header ( UDH) is set for each message, which states the order and message each part belongs to. Due to this special UDH, the length of each combined 7-bit message is shortened to 153 characters (67 characters for UCS-2).

Using Emojis in text messages

You can add Emojis to a text message when using our SMS API. However, Emojis reduce the character limit to 70 characters.