No. Grammarly’s own support page says it is an online application: your computer must be connected to the internet for Grammarly to analyse text and make suggestions. That applies to Grammarly for Windows as well as the browser extension. If you write on a plane, on a train or on a network that blocks cloud services, you need a checker that runs on your PC: Word’s built-in Editor, Edge’s basic spellcheck, Harper or a LanguageTool server you run yourself.
What Grammarly does without a connection
It stops checking. Grammarly’s answer to “Can I use Grammarly offline?” is that it needs a stable internet connection to analyse your text, and its getting-started guide calls it cloud-based software that cannot be used offline. There is no offline mode to switch on and no file to download in advance.
The desktop app does not change this. Installing Grammarly for Windows gives you suggestions in more apps, but each check still goes to Grammarly’s servers.
What still checks your writing offline on Windows
Four options keep working with Wi-Fi off. They differ in where they work and how much they check.
| Tool | Offline behaviour | Where it works | Limits |
|---|---|---|---|
| Microsoft Editor in Word and other Office apps | Microsoft says Editor’s basic functionality stays available without internet, and nothing is sent to Microsoft in that case | Office documents and mail | Only the basic checks; nothing outside Office |
| Microsoft Edge with Basic writing assistance | Spellchecking runs locally on the device | Text boxes in Edge | Spelling only, no grammar |
| Harper | Its Chrome extension does all its work offline | Chrome, plus editor integrations such as VS Code and Obsidian | English only; the system-wide desktop app is for macOS only, as of October 2026 |
| LanguageTool on your own server | The open-source engine runs as a local HTTP server | The LanguageTool browser add-on, pointed at your server | Needs Java and a command line; some features, such as synonyms, do not work |
Word and Office
Microsoft lists Editor among the Office connected experiences that analyse your content, with a footnote: basic functionality of Editor remains available when you are not connected to the internet, or when you turn connected experiences off, and in both cases no content is sent to Microsoft. Advanced refinements such as clarity and conciseness come with a Microsoft 365 subscription, according to the Editor help page. Microsoft does not promise those offline.
Microsoft Edge
Edge offers two levels of writing assistance under edge://settings/languages. With Microsoft Editor selected, Edge sends typed text to a Microsoft cloud service for spelling and grammar. With Basic selected, Microsoft says Edge performs only local spellchecking and sends nothing to the cloud. You keep spelling, and you lose grammar.
Harper
Harper is a free, open-source grammar checker from Automattic that checks on your device. Its Chrome extension does all of its work offline. The catches are language and reach: as of October 2026, Harper supports English only, and its desktop app, the version that checks every text field, runs on macOS, with Windows listed as “not yet”. On Windows, then, you get it in Chrome and in the editors it integrates with, not in Outlook or a messenger.
LanguageTool, self-hosted
LanguageTool’s open-source engine includes an embedded HTTP server. You start it with Java on your own PC, then open the browser add-on’s options, go to Experimental settings and choose “Local server”. Checks then go to your machine instead of LanguageTool’s servers. This route suits people comfortable with a command line; the project’s page is the setup guide.
Test it before you lose the connection
Run this check before a flight. It takes five minutes:
- Turn on airplane mode, or unplug the network cable.
- Open the app you will write in, such as Word, Edge or Chrome.
- Type a test sentence with planted mistakes:
Their going to send the the report tomorow. - Note what gets flagged: the spelling of “tomorow”, the doubled “the” and the wrong “their” are three different checks.
- Turn the connection back on and compare.
The difference between the two runs is the part of your current checker that depends on the cloud.
Where Typeahead fits
Typeahead is not a grammar checker and does not correct anything. It does a different job offline: it suggests how your sentence continues, next to the cursor, in Windows apps such as Word, Outlook, Chrome and WhatsApp. You accept a suggestion with Tab or the Right arrow key, or keep typing to ignore it.
The suggestions come from a compact language model that runs on your PC, so they keep coming with no connection. The guide to offline AI writing assistants explains how that works and what a local model gives up. Typeahead costs $9.99 once, with a 7-day free trial.
A practical offline setup is two tools: one that writes with you, such as Typeahead, and one that checks afterwards, such as Word’s Editor or Harper.
Frequently asked questions
Does Grammarly have an offline mode?
Does Microsoft Word check spelling and grammar without internet?
Is Harper available for Windows?
Does Typeahead check grammar?
Typeahead completes your sentences on your own PC, with or without a connection. Pair it with an offline checker from the list above.
Get Typeahead