Snake Case vs Kebab Case for Names and Labels

Snake case joins words with underscores (monthly_sales_report); kebab case uses hyphens (monthly-sales-report). Use kebab case for URL slugs and many file names, and snake case for variable names in languages where a hyphen means minus. The Case Converter makes both in one click.

Convert a phrase

1. Paste monthly sales report into Input Text.
2. Under Conversion Options, click snake_case. The output is monthly_sales_report.
3. Click kebab-case instead to get monthly-sales-report. The All Conversions list below shows every style at once.

Punctuation is turned into separators, so Q3 report (final).pdf becomes q3_report_final_pdf. The dot before the extension is lost too, so convert the name without the extension and add .pdf back.

Watch out for acronyms

The converter starts a new word at every capital letter that follows another letter. That splits acronyms letter by letter:

API Key Settings  →  a-p-i-key-settings
api key settings  →  api-key-settings

The fix is simple: pick lowercase first, copy the output back into the input, then choose snake_case or kebab-case. The same applies to camelCase input such as userAPIKey, which becomes user_a_p_i_key.

Which one to use where

• URL slugs: kebab case. Google's URL guidelines recommend hyphens rather than underscores to separate words.
• Python, Ruby and SQL names: snake case is the common convention.
• JavaScript variables: neither; camelCase is usual, and monthly-sales would be read as subtraction.
• An existing project: follow its convention instead of adding a second style.

If it doesn't work

• Letters separated by underscores: the input had uppercase acronyms. Lowercase first.
• Output starts with _ or -: the input began with a space or punctuation, such as (final) notes → -final-notes. Delete the leading character before converting, or trim it from the output.
• Renaming files that are already linked: renaming does not update links. Keep a list of old and new names and update references.

Everything runs in your browser. Open the free Case Converter.