How emojis affect SMS character limits

An emoji may look like just one character on screen, but in SMS it can change how the entire message is encoded.

That can reduce the available character limit from up to 160 characters to up to 70 characters.

For businesses sending SMS at scale, this can affect message length, the number of SMS parts sent, and campaign cost.

What happens when an SMS contains an emoji

Most standard SMS messages use GSM 7 encoding. GSM 7 supports a defined set of letters, numbers, and symbols. When a message contains only supported characters, one SMS can contain up to 160 characters.

Emojis are not part of the GSM 7 character set. Adding an emoji normally means the message needs Unicode encoding instead. Once Unicode is used, the limit for a single SMS drops to up to 70 characters.

For longer messages, some of the available space is used to tell the receiving device how the separate SMS parts belong together.

One emoji can create several SMS parts

Imagine a promotional message containing 150 characters.

Without an emoji, it may fit into one GSM 7 SMS. Add an emoji and the message can switch to Unicode. The same message may then need several SMS parts.

The customer will usually still see one continuous message, but several SMS parts may have been sent behind the scenes.

It is not only emojis

Other characters can also cause an SMS to use Unicode. These can include certain accented letters, smart quotation marks, special symbols, and characters from languages that are not supported by GSM 7.

This can be easy to miss when text is copied from a document, website, or another application.

Two characters may look almost identical to the person writing the message while being treated very differently by the SMS system.

Check your SMS before sending

The easiest way to avoid surprises is to check the final message rather than counting characters manually.

LINK Mobility's SMS length calculator shows the number of characters, the encoding used, and how many SMS parts a message requires.

This is especially useful when your message contains emojis, accented characters, special symbols, or several languages.

Use emojis with intention

Emojis can make business messages feel more engaging, personal, and easier to scan. They can work particularly well in promotional messages, reminders, loyalty campaigns, and seasonal communication. But in SMS, an emoji is not only a creative choice. It can also change how the message is encoded and reduce the available character limit.

Before sending, check the final message length, the encoding being used, and how many SMS parts will be required. This is especially important when the message is already close to the character limit.

For shorter messages, adding an emoji may have little practical impact. For longer messages or high volume campaigns, the same emoji could increase the number of SMS parts being sent.

The best approach is simple. Use emojis where they add something to the message, but check the technical impact before the campaign goes live.