Grammar Checker

Paste any text to instantly detect and fix grammar, spelling, punctuation, and awkward phrasing. See every correction explained.

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AI Grammar Checker & Fixer

Paste any text to instantly detect and fix grammar, spelling, punctuation, and awkward phrasing. See every correction explained.

Key Capabilities

Explanations for every correction

Each flagged error is accompanied by an explanation of the grammar rule it violates, making the tool educational rather than just corrective.

Distinguishes errors from style suggestions

The tool separates definitive grammar errors from stylistic suggestions, helping writers make informed decisions.

Academic and professional writing modes

Switch between standard, academic, and professional modes to adjust the checker expectations.

How to Use

Paste or type your text

Paste the text into the input area. The tool works in real time as you type.

Review highlighted errors

Errors are underlined in red; style suggestions in blue. Click any highlighted item to see the explanation.

Apply corrections and export

Accept individual corrections or dismiss ones that do not apply. Copy the corrected text.

Common Use Cases

ESL professionals polishing correspondenceA business analyst writing in English as a second language can run documents through the checker before sending to clients.
Students self-editing essaysAn undergraduate can catch agreement errors, tense inconsistencies, and punctuation mistakes before submission.
Copywriters reviewing client deliverablesA freelance copywriter can run each piece through the checker as a final quality gate.

Frequently Asked Questions

Does it explain the grammar mistakes?

Yes. Unlike basic spellcheckers that only autocorrect, our grammar checker provides clear explanations for each flagged error, helping you understand the mistake and improve your writing.

Are there any word limits or premium features?

No. The grammar checker is completely free to use without daily limits or premium paywalls. It checks entire documents locally in your browser.

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AI-Powered Document Intelligence — How Our Tools Work

Large Language Models for Document Processing

DoctorDocs AI tools are powered by state-of-the-art large language models (LLMs) including our in-house vision model trained on 1M+ labelled documents for cloud processing and quantized open-source models for in-browser execution. LLMs are neural networks trained on trillions of words of text, enabling them to understand context, grammar, tone, and meaning at a level approaching human comprehension. When you paste text into our AI Summarizer, the model reads the entire document, identifies key themes and facts, and generates a concise summary — not by copying sentences, but by genuinely understanding and rephrasing the content.

In-Browser AI vs Cloud AI

Some of our AI tools run entirely in your browser using WebAssembly and ONNX Runtime. These in-browser models are smaller (typically 50-200MB) and run on your device's CPU, meaning your text is never sent anywhere. The trade-off is that in-browser models are less capable than full cloud models. Our cloud-powered tools (like the Document Summarizer and Translator) send your text to our secure cloud models via encrypted API calls. The text is processed in real-time and immediately discarded — it is never stored, logged, or used to train models. We clearly label which tools use cloud processing and which are fully local.

AI Text Detection Explained

Our AI Text Detector uses a specialized RoBERTa neural network model (a variant of BERT) that has been fine-tuned to distinguish human-written text from AI-generated text. The model analyzes patterns like vocabulary diversity, sentence length variation, perplexity (how predictable the next word is), and burstiness (variation in sentence complexity). Human writing tends to have more irregular patterns — mixing short and long sentences, using unexpected vocabulary, and making occasional grammatical quirks. AI-generated text tends to be more uniform and predictable. The entire model downloads to your browser and runs locally, so your text is never sent to any server.

Limitations and Responsible Use

AI tools are powerful but imperfect. Summaries may occasionally miss nuances. Translations may not capture cultural idioms perfectly. Grammar checkers may flag stylistic choices as errors. AI text detection has a baseline accuracy rate and can produce both false positives and false negatives. We encourage users to treat AI tool outputs as helpful starting points that benefit from human review. For critical documents — legal contracts, medical reports, academic submissions — always have a human expert review the AI output before taking action.