A proper noun is a specific name for a particular person, place, organization, or thing. In English, proper nouns are almost always capitalized. Examples include Albert Einstein (person), Paris (place), Microsoft (organization), and Friday (day). They differ from common nouns like "city," "scientist," or "company," which refer to general categories.

Our tool uses a two-pronged approach: First, it matches text against a built-in dictionary of thousands of common proper nouns (names, places, organizations). Second, it applies heuristic rules to detect capitalized word patterns that resemble proper nouns — such as consecutive capitalized words like "Grand Canyon" or "Supreme Court." All processing happens locally in your browser — no data is ever sent to any server.

Dictionary-based matches are highly reliable for the names in our database. Heuristic matches (dashed underline) are suggestions and may include false positives — for instance, the first word of a sentence or common capitalized abbreviations. We recommend reviewing all "possible" matches manually. Our dictionary covers thousands of common English names, major world cities, countries, Fortune 500 companies, and well-known institutions.

Absolutely. All text processing is performed entirely within your web browser using client-side JavaScript. Your text never leaves your device, is never transmitted over the internet, and is never stored on any server. You can use this tool offline after the page loads. This makes it ideal for sensitive documents, legal texts, or confidential business content.

Common use cases include: proofreading and editing (ensuring proper nouns are consistently capitalized), academic research (quickly identifying all named entities in a paper), content writing (verifying name spellings), SEO optimization (checking that key brand and location names appear correctly), language learning (helping English learners recognize proper nouns), and data preparation for NLP tasks.

Currently, the tool uses a fixed built-in dictionary. However, any capitalized word or phrase not in our dictionary will still be flagged as a "possible proper noun" (with a dashed yellow underline). This ensures that uncommon names, niche brands, or newly coined terms are not overlooked. Future versions may support custom dictionary uploads.

Words that are capitalized mid-sentence trigger our heuristic detector. This includes genuine proper nouns not in our dictionary as well as capitalized common nouns used for emphasis or stylistic reasons. Words like "I" (the pronoun) are excluded from detection. If you notice consistent false positives, simply ignore the dashed-underline highlights and focus on the solid-underline (dictionary-confirmed) matches.

This tool is optimized for English text. Proper noun capitalization rules differ across languages (e.g., German capitalizes all nouns, not just proper ones). While the dictionary-based detection may still identify some international names and places, the heuristic detection is tailored to English conventions. For non-English texts, results may be less accurate.