Case Converter - Uppercase, Lowercase & Title Case

Change capitalization, sentence case and code naming styles. Paste text or import .txt, then copy or download the result.

Case Converter is a text case changer for pasted text and imported .txt files. Your original stays visible beside the result. Convert uppercase to lowercase, turn a sentence into capitals, format a heading, or change a list of names into a code naming style. Twelve modes are available in one workspace, with the source on the left and the result on the right. ✍️ Change case for writing and headings • Use UPPERCASE for all capitals or lowercase to remove them. • Sentence case makes a mechanical first pass at sentence and line starts. • Capitalize Words starts each word with a capital, while Title Case treats common small English words differently when that option is enabled. This lets you choose the capitalization you actually need instead of applying one rule to everything. A heading and a sentence are different jobs: review proper names, abbreviations and editorial style after conversion. The tool changes letter case; it does not rewrite or proofread your wording. 💻 Naming styles for code and data The code modes include camelCase, PascalCase, snake_case, kebab-case and CONSTANT_CASE. Use them to prepare names for variables, fields, filenames or configuration entries. Code modes split words, remove punctuation and join the parts using the selected convention. Conversion works line by line, so a pasted list can become a list of consistently styled names. Acronym boundaries are recognized: HTTPServer can become http_server. Check the result against the naming rules of your target language or application, because changing case alone cannot guarantee that a name is a valid identifier. 🔄 Invert or alternate the letters • Invert case swaps uppercase and lowercase letters. • Alternating case produces a mixed-case pattern. These are separate modes from reversing text: the characters stay in their original order. For ordinary writing modes, spacing, punctuation and line breaks are retained unless an applicable cleanup option changes them. Trim spaces is available when you want to remove extra space at the edges. Review names, abbreviations and any manually edited wording before copying the result. 📋 Edit, copy or save the result Paste your text, choose a mode and watch the result update after a short typing pause. You can also edit the result directly. Copy and Download .txt use the current result, while Clear and Import .txt sit beside the source. Import or drop a .txt file encoded as UTF-8, or UTF-16 with a byte-order mark. The source counter shows words and Unicode characters. Standard editing and undo shortcuts stay available in the text fields. Export before closing the tab if you want to keep the converted text. 📏 Character handling and practical limits Case changes use standard Unicode mappings, including Cyrillic and accented letters. Locale-specific rules such as Turkish capitalization are not applied. A letter can sometimes expand during a case change, and a multi-part emoji can count as more than one Unicode character. Text-file import supports up to 2 MB. The source allows up to 1,000,000 Unicode characters and the result up to 3,000,000. Oversized pasted text is rejected without quietly trimming the end. The conversion happens in the extension tab; your text and imported files are not uploaded, and the extension does not read the pages you visit.