Snake Case Converter — Free Online
Paste a phrase, column header or variable name and get snake_case back instantly — lower case words joined by underscores, the naming style Python, Ruby and PostgreSQL expect. Switch to camelCase, kebab-case or lowercase when you need a sibling format for the same string. Everything runs in your browser; nothing is uploaded.
How to use the snake case converter
- Paste or type the text you want in snake_case into the first box.
- Snake case is already selected — the result updates live below.
- Copy the output, or tap camelCase or kebab-case if the destination expects a different style.
What snake_case is for in real projects
Snake case — every letter lower case, words separated by underscores — is the default for Python function and variable names in PEP 8, for Ruby method names in many style guides, and for SQL column names when teams want readable identifiers without quoting. JSON APIs that serve Python backends often expose snake_case keys because that is what serializers emit naturally.
People search for a snake case converter when they inherit a spreadsheet export with Title Case headers, a camelCase API response they need to map into a database schema, or a product name pasted from marketing copy. Converting in one pass beats hand-typing twenty column renames before an import.
It is not the same as screaming snake case (UPPER_SNAKE for constants) or kebab-case for URLs. This tool targets ordinary lower snake_case. If you need constants in ALL CAPS, run uppercase on the result or start from the uppercase converter page.
How the converter splits words
The engine looks for word boundaries: spaces, hyphens, underscores and transitions from lower to upper case inside a single token. “userProfileId” becomes user, profile, id — then snake_case joins them as user_profile_id. “HTTPResponse” keeps HTTP as one word when it arrives fully capitalised, which matches how many teams name acronyms in snake_case (http_response vs h_t_t_p_response is a taste call; skim acronyms before you commit).
Numbers stay attached to the word they touch: “version2Release” becomes version2_release. Punctuation that is not a separator is dropped. Lines are processed independently so a multi-line paste of field names converts row by row without merging lines into one identifier.
Mixed input from PDFs may still carry stray line breaks. If a header arrived wrapped, run remove line breaks first, then snake case — or paste one header per line here when each line should become its own identifier.
Snake case vs camelCase and kebab-case
JavaScript and Java prefer camelCase for variables and methods; URLs and CSS class names prefer kebab-case; Python and Postgres prefer snake_case. The same product feature might be user_settings in the database, userSettings in the React prop and user-settings in the docs URL. This page keeps snake as the default but exposes the sibling buttons so you do not hunt three different tools for one rename job.
Database migrations often need snake_case column names even when the ORM model uses camelCase in TypeScript. Paste the model field list, copy snake_case output into the migration file, and keep the application layer unchanged. For OpenAPI specs that mandate snake_case query parameters, batch-convert the parameter list from a camelCase draft.
File names on disk are a separate convention — many teams use kebab-case for slugs and snake_case only inside code. Use the kebab button when the output is for a URL segment rather than a Python module attribute.
Frequently asked questions
Paste the phrase into the box. Snake case is applied instantly — lower case words joined by underscores, with no signup.
Python variables, Ruby methods, SQL columns and many JSON APIs use snake_case — readable words without camelCase capitals.
Yes. camelCase and PascalCase strings are split at capital letters before underscores are inserted.
Snake case uses underscores (user_id). Kebab-case uses hyphens (user-id) and is common in URLs. Switch modes with one tap.
Yes. Paste one header per line or a space-separated list; copy the result into your import script or ORM model.
No. Conversion is JavaScript in your browser — safe for internal schema names and unpublished API drafts.
Yes. Digits stay with the adjacent word, so version2 becomes version2 in the output token list.
Convert to snake_case here, then use the lowercase/uppercase sibling or uppercase converter for ALL_CAPS constants.
Yes — tap the camelCase button after pasting. The same input can be copied in both styles without retyping.
Yes — no character paywall, watermark or account required.
Related tools
- Camel Case ConverterTurn a phrase, database column or file slug into camelCase — first word lower case, each following word capitalised, no spaces.
- Lowercase Converter FreeConvert to lowercase free in one paste: this lowercase converter turns ALL CAPS into small letters instantly — perfect for “to lowercase”, “lower case converter” and “lowercase online” searches.
- Remove Line Breaks From TextText copied from a PDF, email client or terminal often arrives broken into short hard-wrapped lines.
- Title Case ConverterPaste a heading and get properly capitalised title case back as you type.
Runs entirely in your browser — your files and text never leave this device. Last reviewed August 24, 2026.