UPPER, lower, Title & Sentence case — 100% free, runs in your browser
Retyping text just to change its capitalisation wastes time, and doing it by hand introduces mistakes. This handles the everyday cases plus the programming conventions — camelCase, snake_case and kebab-case — which are useful when naming variables, files or URLs.
Title Case Capitalises Every Word. Sentence case capitalises only the first word of each sentence, which is what most style guides now prefer for headings.
For URLs and file names. Search engines read hyphens as word separators, which underscores do not.
Case conversion only applies to scripts that have upper and lower case. Bengali does not, so the text passes through unchanged.