The Grammar Index

A complete English grammar reference — searchable, authoritative, and yours for life. One licence works across iPhone, iPad, Safari Web Browser

The Grammar Index is a complete reference to English grammar, designed for writers, editors, teachers, students, and anyone whose work depends on getting language right.

Search clear, authoritative entries covering everything from punctuation and parts of speech to clauses, voice, mood, register, and the structural patterns underlying English sentences. Each entry is concise, example-rich, and free of jargon — written to answer a real question, not to show off terminology.

WHAT'S INSIDE • Fast full-text search across the entire reference • Detailed entries with worked examples • Cross-references between related concepts • Works fully offline once your device is activated • Clean, distraction-free reading layout tuned for iPhone, iPad and Safari Web Browser

WHO IT'S FOR • Writers and editors who need quick, reliable answers mid-draft • Teachers preparing lessons or marking student work • ESL and EFL learners building deep grammar knowledge • Translators and copy editors who need precise terminology • Students studying English, linguistics, or composition

ONE LICENCE, EVERY DEVICE Your Grammar Index licence works across iPhone, iPad and Safari Web Browser. Buy once, use forever — no subscriptions, no recurring fees. The Individual licence covers two devices; the Team licence covers thirty; the Institution licence scales for schools, colleges, and universities.

OFFLINE-FIRST Once your device is activated with your licence key, the entire reference is available without an internet connection. Perfect for classrooms, exam halls, planes, and anywhere connectivity is patchy or unavailable.

ACTIVATION A licence key (format: GI-XXXX-XXXX-XXXX) is required to use the app. Licences are sold separately and arrive by email after purchase. Enter your key on first launch to activate the device.

PRIVACY The Grammar Index does not track you, does not show advertisements, and does not collect data about how you use the app. Your licence key is the only identifier sent to our servers, and only for the purpose of validating your device against your licence's allowance.

SUPPORT Email support@grammarindex.com for help with your licence, your devices, or the app itself.