A grammar checker is a software tool designed to identify and correct grammatical errors in written text. It helps users improve their writing by highlighting mistakes such as incorrect verb tenses, subject-verb agreement, and punctuation errors. Many grammar checkers also provide suggestions for rephrasing sentences to enhance clarity and style. These tools are commonly integrated into word processing programs, email clients, and web browsers. Some popular grammar checkers include Grammarly, Microsoft Word's Editor, and ProWritingAid. By using a grammar checker, individuals can produce clearer, more professional writing, making it a valuable resource for students, professionals, and anyone who writes regularly.