Change capitalization without retyping

Case Converter

Convert text to lowercase, uppercase, sentence case, headline-style title case, or toggled case locally while preserving spacing and line breaks.

01Private by designYour text stays in this browser tab.
02Bounded and responsiveUp to 500,000 characters in each main text field.
03Ready to reuseCopy the result or download a branded TXT file.

No text upload to Nirmion

Counting and transformations run locally. Nirmion does not send the text in this workspace to an API.

Product guide

Pick the case pattern that fits the destination

Lowercase and uppercase are direct locale-aware transformations. Sentence and title modes apply editorial heuristics, while toggle mode swaps the case of each cased grapheme for recovery or testing.

Step A

Prepare the input

Paste plain text with the spacing and line breaks you want to keep. The converter does not parse HTML, Markdown semantics, code strings, or protected brand terms.

Step B

Choose the rule

Choose lowercase for normalization, uppercase for intentional emphasis, sentence case for prose starts, title case for English-style headings, or toggle case to invert existing capitalization.

Step C

Review the output

Read the complete result before replacing production copy. Proper nouns, acronyms, camelCase identifiers, Turkish dotted I, and language-specific title conventions can require manual correction.

How it works

Locale-aware casing plus limited editorial heuristics

Direct modes use JavaScript locale casing. Sentence case lowers the source and capitalizes the first letter after common sentence-ending punctuation. Title mode capitalizes words, preserves existing all-cap acronyms, and keeps a small English minor-word list lowercase away from the first and last word. Toggle mode swaps cased graphemes while leaving numbers and punctuation unchanged.

Useful when

Normalize inconsistent capitalization quickly

The converter removes repetitive retyping while leaving the final editorial decision with you.

Repair copy pasted from spreadsheets, forms, OCR, or all-caps source material before editing.
Create consistent labels, headings, catalog values, or test fixtures from mixed-case input.
Compare title and sentence treatments for a headline, then manually restore required brand names and acronyms.

Questions answered

Case Converter questions

Practical boundaries matter with text tools. These answers explain what is measured, what is retained, and when a manual review is still needed.

Will title case follow my style guide?

Not exactly. It uses a practical English minor-word list and preserves all-cap acronyms. AP, Chicago, sentence-style headings, and other house rules differ, so use the result as a first pass.

Does conversion remove spaces or punctuation?

No. Case modes preserve the source sequence and change cased letters. Separate Whitespace Cleaner or Line Break Remover tools are better for structural cleanup.

Can I use it for source code?

You can, but it is unsafe for semantic identifiers because changing case can break variables, paths, strings, and APIs. Use language-aware refactoring tools for code.

Privacy and retention

Your draft stays on your device.

Nirmion performs these operations with browser JavaScript. The workspace does not call the catalogue API with your source text, and completed-job content is kept only in this component memory for re-download.

A downloaded file remains in your browser downloads, device storage, backups, and any location where you share it. Clear or close the page when working on a shared device, and avoid pasting secrets into extensions or third-party clipboard managers.

Tool details

Five useful case modes in a private workspace

Nirmion Case Converter handles lowercase, uppercase, sentence case, title case, and toggle case in the browser. It preserves whitespace and punctuation, reports changed positions, and supports up to 500,000 source characters for editorial cleanup, catalog work, content migration, and testing.

The output downloads as text_nirmion_tools_case_converted.txt and the active form clears after download. Because proper nouns and style rules require context, Nirmion presents title and sentence conversion as reviewable heuristics rather than guaranteed copyediting.