Best English Grammar Apps for iPhone, iPad and Mac, Tested

An English grammar app does three jobs at once. It catches mechanical errors such as misspellings, doubled words and missing apostrophes, it flags grammar and punctuation problems like subject to verb disagreement or a comma splice, and the better ones add a layer of style and clarity coaching that nudges wordy or unclear sentences into shape. The three names worth your time are Grammarly, ProWritingAid and LanguageTool, and Apple's own built in proofing tools sit quietly behind all of them.

In our testing, the people who get the most value fall into clear groups. Non native English speakers gain the most, because a corrector explains patterns rather than just fixing them. Students and professionals who write all day get a fast safety net that catches the typos that creep in under deadline. Casual writers who fire off the occasional email may find Apple's free built in checking is already enough. If you are not sure which camp you are in, start free and upgrade only when you hit the limits.

The phone and tablet setup is nearly identical, and the part most people rush is the keyboard. Here is the path we followed for the deepest correction:

1. Install and sign in. Download the app from the App Store, open it, and create a free account. The account matters more than it looks because it syncs your saved words and tone settings across every device.
2. Add the custom keyboard. Open Settings, go to General, then Keyboard, then Keyboards, and tap Add New Keyboard. Choose the grammar app from the list.
3. Grant Full Access. Tap the keyboard you just added and turn on Allow Full Access. This is what lets the keyboard check text as you type in Mail, Notes, Messages and the rest. iOS shows a privacy warning here, which is normal.
4. Switch keyboards while typing. Tap and hold the globe key on the keyboard, then pick the grammar keyboard. Corrections now appear inline.

On iPad the steps are the same, and if you use a Magic Keyboard or Smart Folio the corrections still surface as you type. We found the iPad especially comfortable for longer drafts because the bigger screen shows more of the suggestion cards at once.

The Mac is where grammar checking gets genuinely powerful, and there are two routes. The first is the desktop app, which installs a system wide helper that underlines errors inside almost any app, including Mail, Pages, TextEdit and Notes. The second is the browser extension for Safari or Chrome, which is the one to use if most of your writing happens in Gmail, Google Docs or web forms.

We recommend installing both. After downloading the desktop app, macOS will ask you to grant it Accessibility permission in System Settings, then Privacy and Security, then Accessibility. This is the step that lets the app read and correct text in other windows, so without it you will see the app open but no underlines anywhere. For the browser side, add the extension from the relevant store and pin it so the suggestion count is always visible. One tip from our testing: if corrections stop appearing in a specific app, quit and reopen that app rather than the corrector, because the helper hooks in when the target app launches.

After the novelty wore off, only a handful of features earned their place in daily writing. These are the ones we kept reaching for:

• Real time underlines. Red for spelling, blue or green for grammar and clarity. Tapping a suggestion to accept it was consistently faster than a manual proofread.
• Tone and clarity checks. The best tools warned us when a sentence read as harsh, hesitant or overly wordy. That feedback improved our emails far more than any missed apostrophe.
• Explanations, not just fixes. A short note on why a comma was wrong taught us something. Apps that silently swapped a word left us no smarter the next time.
• A personal dictionary. Adding names, brand terms and jargon once stopped the endless false flags on words the app simply did not know.
• Goal setting. Telling Grammarly or ProWritingAid the audience and intent of a document changed its advice in a way that genuinely fit the moment.

In our testing the explanations were the quiet hero. If your aim is to genuinely improve, rather than to clean a single document, choose a tool that teaches as it corrects. That same principle is why we pair grammar tools with a structured course, and our notes on that live in the guide to the best Duolingo features.

A few habits made these apps far more useful, and none of them are obvious on day one. First, treat the app as a second opinion, not a verdict. We read every flagged sentence and ignored roughly one suggestion in five, usually around deliberate style choices or casual phrasing in a text to a friend.

Second, lean on the device you write the most on. If you draft long pieces on a Mac, set up the desktop app first and treat the phone as the quick checker on the go. If most of your typing is messages and social posts, the iPhone keyboard is where the value lives. Third, build your personal dictionary early; adding ten or so common names and terms in the first week kills most of the annoying false positives. Fourth, use keyboard shortcuts on the Mac, where pressing the suggestion shortcut to accept a fix keeps your hands on the keys. Finally, give the tone or goal setting an honest answer about your audience, because formal versus casual completely changes the advice you get back.

The three leading tools suit different writers, and after living in all of them we would not call any single one the universal winner.

Grammarly is the most polished and the easiest to recommend to most people. Pros: excellent real time underlines, the best tone detection we tested, and a clean experience across iPhone, iPad and Mac. Cons: the most useful clarity and rewrite suggestions sit behind a fairly pricey subscription, and it can be opinionated about style.

ProWritingAid is built for long form writing. Pros: deep reports on pacing, repetition, sentence length and readability that suited our long report and would suit essays or manuscripts well. Cons: the interface is busier, the mobile experience is weaker than Grammarly's, and all that analysis can be overwhelming for short notes.

LanguageTool is our pick for the privacy minded and the multilingual. Pros: a generous free tier, support for many languages and English variants, and an option to self host so your text never touches a third party server. Cons: the style coaching is lighter than Grammarly's, and the apps feel a little less refined.

To see how each fits alongside flashcards, readers and the rest of a learning setup, browse the full Education and Learning collection or start from our best education apps for iPhone roundup.

Before you pay for anything, it is worth knowing how much Apple already does for free. On every iPhone, iPad and Mac, the system catches spelling errors and a fair amount of basic grammar, and on the Mac you can run a full check by going to Edit, then Spelling and Grammar, then Check Document Now inside apps like Pages and TextEdit. In our testing this caught a surprising share of everyday slips, and it never sends your words to a server.

Where Apple falls short is depth. It rarely explains why something is wrong, it has no real tone or clarity coaching, and it misses the more subtle grammar patterns that trip up non native speakers. We think of it as a solid floor: more than enough for casual writing, but not a replacement for a dedicated tool if you write seriously or want to improve. The smart move is to keep Apple's checking on as a backstop and add a third party app only where you need more.

A few issues come up again and again, and most have quick fixes:

• The keyboard does not correct anything on iPhone. You almost certainly skipped Allow Full Access. Go back into Settings, Keyboard, tap the app keyboard and enable it.
• No underlines on the Mac. The desktop app needs Accessibility permission under System Settings, Privacy and Security. Grant it, then quit and reopen the app you are writing in.
• Suggestions feel laggy while typing. On older hardware the always on checking can add a slight delay. Turning off real time checks and running a manual scan at the end fixed it for us.
• The app flags correct sentences. Add the word or name to your personal dictionary, or simply dismiss the suggestion. Creative phrasing and intentional fragments will always trigger false flags.
• Settings did not sync between devices. Confirm you are signed into the same account everywhere; this is the single most common cause.

Grammar apps are unusually powerful because, by design, they can see everything you type. That deserves a clear eyed look. Granting Full Access to a keyboard on iPhone, or Accessibility to a Mac app, is what makes correction possible, but it also means the app processes your text, often by sending it to the cloud for analysis. The reputable apps state plainly that they do not log password fields, and we read those policies before enabling anything.

Our practical rules after testing: turn correction off inside your banking and password apps, both for privacy and because flagged account numbers are just noise. Keep anything genuinely sensitive in an app where the corrector is disabled. If privacy is a top concern, LanguageTool's self hosting option keeps your text on your own machine, which no other mainstream tool offers. For a wider look at locking down what apps can see, our guide to privacy settings on iPhone is a good companion read.

Every tool here has a usable free tier and a subscription that unlocks the deeper coaching. The honest summary from our testing is that the free versions catch spelling and basic grammar well, while the advice that actually elevates your writing, the clarity rewrites and tone work, usually sits behind a monthly plan.

Grammarly's free tier handles the essentials, with the rewrite and tone tools reserved for premium. ProWritingAid offers a free plan with a checking limit, and its premium unlocks the full reports along with a one time lifetime option that long term users may prefer over a subscription. LanguageTool has the most generous free tier of the three, with a premium plan that adds advanced style checks. We thought a paid plan was clearly worth it for heavy writers, students with frequent deadlines and non native speakers actively improving, and pure overkill for someone sending the occasional email who is well served by the free tier or Apple's built in tools.

If you want one app and you are happy across iPhone, iPad and Mac, Grammarly is the easiest to recommend. Its real time underlines, tone detection and polished cross device experience made it the tool we left installed on every screen, and the free tier alone is a real upgrade over typing unaided.

If you write long documents and care about pacing, repetition and readability, ProWritingAid is the more serious instrument, especially on the Mac. If privacy or multiple languages matter most, LanguageTool is the thoughtful choice, with a free tier good enough that many people never need to pay. And whichever you pick, leave Apple's built in checking switched on as a backstop. A pattern several writers we know swear by, and one we ended up agreeing with, is using a fast everyday corrector for speed and a deeper tool for the documents that really matter. For more ways to round out a learning setup, our best education apps for Mac guide is a good next stop.