Input
Output

snake_case joins words in lower case with underscores — user_name, parse_html_input. It is the standard for variables and functions in Python and Ruby, and for column names in most SQL databases. This converter accepts camelCase, PascalCase, kebab-case or a plain phrase and normalises all of them.

How to use

  1. Paste the identifier or phrase — userName, user-name and user name all work.
  2. Word boundaries are detected from case changes and separators, then joined with underscores in lower case.
  3. Copy the result into your code or schema.

FAQ

How does it split camelCase?

At each transition from a lower-case letter to an upper-case one, so parseHtmlInput becomes parse_html_input.

What about SCREAMING_SNAKE_CASE?

Use the CONSTANT_CASE converter. It applies the same word splitting and then upper-cases everything, which is the usual style for constants.

Is it safe for SQL column names?

snake_case avoids the quoting that mixed-case identifiers require in PostgreSQL, which is why it is the common convention. Check reserved words separately.