Generating the euro sign using a computer depends on the operating system and national conventions. Some mobile phone companies issued an interim software update for their special SMS character set, replacing the less-frequent Japanese yen sign with the euro sign. Later mobile phones have both currency signs.

The euro is represented in the Unicode character set with the character name EURO SIGN and the code position U+20AC (decimal 8364) as well as in updated versions of the traditional Latin character set encodings. In HTML, the € entity can also be used. The HTML entity was only introduced with HTML 4.0, shortly after the introduction of the euro, and many browsers were unable to render it. The alternative was to use € instead, with 128 (80 hexadecimal) being the code position of the euro sign in most Windows 125x encodings.

An implicit character encoding, along with the fact that the code position of the euro sign is different in common encoding schemes, led to many problems displaying the euro sign in computer applications. While displaying the euro sign is no problem as long as only one system is used (provided an up-to-date font with the proper glyph is available), mixed setups often produced errors. One example is a Content management system where articles are stored in a database using a different character set than the editor's computer. Another is legacy software which could only handle older encodings such as ISO 8859-1 that contained no euro sign at all. In such situations, character set conversions had to be made, often introducing conversion errors such as a question mark (?) being displayed instead of a euro sign.

Care has been taken to avoid replacing an existing obsolete currency sign with the euro sign. That could create different currency signs for sender and receiver in e-mails or web sites, with confusions about business agreements as a result.

The Compose key sequence for the euro sign is =E. On many European national keyboard layouts, the symbol can be entered as AltGr + E, on others as AltGr + 4 or AltGr + 5, according to official recommendations.