The en dash, en rule, or nut dash – is traditionally half the width of an em dash. In modern fonts, the length of the en dash is not standardized, and the en dash is often more than half the width of the em dash. The widths of en and em dashes have also been specified as being equal to those of the upper-case letters N and M, respectively, and at other times to the widths of the lower-case letters. The en dash is encoded in Unicode as U+2013 (decimal 8211) and represented in HTML by the named character entity –. The en dash is sometimes used as a substitute for the minus sign, when the minus sign character is not available since the en dash is usually the same width as a plus sign and is often available when the minus sign is not.