Base62

Base62 is a numeral system using 62 distinct characters to represent numbers. It is commonly used as a method for creating short, human-readable identifiers from numerical data, particularly in contexts like URL shortening and generating unique keys.

The 62 characters typically consist of the digits 0-9, the uppercase letters A-Z, and the lowercase letters a-z. The order of the characters matters, as it defines the place value of each character within the base-62 representation. Typically, 0-9 are ordered first, followed by A-Z, and then a-z, but other orderings are possible.

Base62 is favored over other bases, such as hexadecimal (base-16) or base-36 (using digits 0-9 and uppercase letters A-Z), for its balance between readability and efficiency. It utilizes a greater range of characters than base-36, leading to shorter representations for the same numerical value. Unlike hexadecimal, which is often more compact than decimal representation, base62 often provides a shorter and more human-friendly equivalent without requiring special characters.

The primary application of Base62 lies in creating concise and memorable identifiers. Converting a large numerical ID into a Base62 string significantly reduces the length of the identifier, making it easier to share, remember, and transcribe. The case sensitivity of the encoding also adds to its ability to create more unique combinations compared to a case-insensitive system.

When converting a number to Base62, one effectively performs successive divisions by 62, collecting the remainders at each step. These remainders, each between 0 and 61, are then mapped to the corresponding Base62 characters. The process is reversed when converting from a Base62 string back to a number.