I used five AI keyboards as my daily driver for a week each. Same phone (iPhone 16 Pro), same apps (Messages, Mail, Notes, Slack), same test: 10 sentences with grammar errors, 5 tone-change requests, and 5 translations. Here’s what I found.

What “AI Keyboard” Actually Means in 2026

The term gets thrown around loosely. Some keyboards use AI for better autocorrect predictions. Others bolt on ChatGPT-style text generation. A few do grammar checking, translation, or tone adjustment.

Apple added Writing Tools to iOS 18.1 as part of Apple Intelligence, which brought basic AI text features to the system level. But it only works on iPhone 15 Pro and newer, and the capabilities are limited compared to what third-party keyboards offer.

For this comparison, I focused on keyboards that go beyond autocorrect — ones that can fix grammar, rewrite text in different tones, translate, or generate text. Plain autocorrect improvements (which SwiftKey and Gboard both do well) are a bonus, not the main criteria.

How I Tested

Each keyboard got seven days as my only keyboard. I used it for all typing — casual texts, work emails, quick notes, Slack messages. At the end of each week, I ran a standardized test:

Grammar test: 10 sentences with common errors (their/they’re, could of/could have, run-on sentences, subject-verb agreement, comma splices). I checked how many each keyboard caught.

Tone test: 5 casual sentences that I asked each keyboard to make professional, and 5 professional sentences to make casual. I judged whether the result sounded natural.

Translation test: 5 English sentences translated to Spanish, French, Japanese, Korean, and Arabic. I checked accuracy with native speakers.

Not every keyboard could do all three tests. That’s telling in itself.

1. Grammarly Keyboard

Price: Free tier (basic grammar) / $30/month or $144/year (Premium)

Grammarly’s grammar engine is the best I’ve tested. Out of my 10 test sentences, it caught all 10 errors. It flagged the subtle ones too — a dangling modifier that every other keyboard missed, and a comma splice that most people wouldn’t even recognize as wrong.

The Premium tier adds clarity and engagement suggestions, full-sentence rewrites, and tone detection. The tone detection is interesting — it tells you if your message sounds “formal,” “friendly,” “direct,” or “concerned” before you send it. But it doesn’t let you actively change the tone the way other keyboards do. It’s descriptive, not prescriptive.

The keyboard interface is clean. Errors get underlined in real time, and tapping the underline shows the suggestion with an explanation. The explanations are genuinely useful if you want to learn why something is wrong, not just fix it.

What Grammarly doesn’t do: translate, clipboard history, custom text actions, or any text generation. It’s purely a grammar and writing quality tool. If you need translation, you’re installing a second keyboard or switching to the Translate app.

The price is the elephant in the room. $30/month is more than most people pay for their music streaming service. The free tier is useful but limited — it catches basic errors but misses the nuanced stuff that makes Grammarly worth using.

Grammar score: 10/10 Best for: Professional writers, content creators, non-native English speakers who prioritize grammar accuracy above everything else.

2. Microsoft SwiftKey

Price: Free

SwiftKey has been around since 2010 and Microsoft bought it in 2016. It’s arguably the best keyboard for pure typing speed. The swipe typing is excellent, the predictions learn your vocabulary fast, and it handles bilingual typing (switching between languages mid-sentence) better than any other keyboard I’ve tested.

Microsoft has added some AI features through Copilot integration. You can tap the Copilot icon to generate text, get suggestions, or rewrite passages. In practice, this is more like having a mini ChatGPT in your keyboard than a writing tool — it’s good for drafting from scratch but less useful for fixing text you’ve already written.

For my grammar test, SwiftKey caught 4 out of 10 errors. It fixed the obvious ones (spelling-adjacent errors, missing apostrophes) but missed grammatical structure issues entirely. The tone change test wasn’t really applicable since SwiftKey doesn’t have a dedicated tone-change feature. Copilot can theoretically do it, but the workflow is clunky — you’d copy your text, open Copilot, ask it to rewrite, copy the result, and paste back.

No translation feature built into the keyboard (you’d have to use Copilot for that too). No clipboard history.

Grammar score: 4/10 Best for: Fast typists, swipe typing fans, bilingual users who switch languages frequently.

3. Google Gboard

Price: Free

Gboard is the Swiss Army knife of keyboards. It has translate built in, voice typing, GIF search, Google Search, a floating keyboard mode, one-handed mode, and emoji search. It’s an impressive package for a free keyboard.

The autocorrect is a step up from Apple’s stock keyboard. Predictions are more contextual and it adapts to your style faster. But like SwiftKey, there’s no dedicated grammar checking. My 10-sentence grammar test: Gboard caught 3 errors, all spelling-adjacent.

The translate feature is the standout. Tap the Google icon, select Translate, pick a language, and type. Your text gets translated in real time as you type. It’s powered by Google Translate, so language coverage is massive — over 100 languages. The quality is comparable to the Google Translate app.

The limitation of Gboard’s translate: it only translates what you type, not incoming text. Someone sends you a message in Korean and you want to understand it? You’ll have to copy it and use Google Translate separately. It’s a one-way tool.

No tone change, no text rewriting, no clipboard history. The AI features are basically autocorrect and translate.

Grammar score: 3/10 Best for: Users who want a free keyboard with translate, search, and GIF integration. People in the Google ecosystem.

4. CleverType

Price: Free tier / $5.99/month or $39.99/year (Premium)

CleverType is a newer entrant that’s trying to compete directly with Grammarly at a lower price. It has grammar checking, tone adjustment, and text rewriting. The interface is clean and the AI features are front and center.

Grammar performance: 7 out of 10 errors caught. It handled subject-verb agreement and tense errors well but missed the comma splice and dangling modifier. Not Grammarly-level, but noticeably better than SwiftKey or Gboard.

The tone change feature works. I could take a casual text and make it professional, or vice versa. The results were usable — not perfect, but I only had to tweak a word or two maybe 30% of the time.

Translation support is limited compared to the others. CleverType covers about 15 languages. If your language isn’t in the list, you’re out of luck.

No clipboard history. No custom actions. The feature set is narrower than LudyType but broader than Grammarly.

The $5.99/month subscription makes it cheaper than Grammarly but more expensive than LudyType’s one-time purchase over any time horizon longer than about four months.

Grammar score: 7/10 Best for: Users who want Grammarly-style features at a lower monthly price and can live with slightly less grammar accuracy.

5. LudyType

Price: Free tier (70 lifetime actions, 10/day) / $4.99/month / $19.99/year / $19.90 lifetime

LudyType has the widest feature set of any keyboard I tested. Grammar fixing is one of 20+ AI actions that include tone changes (professional, casual, friendly, confident, diplomatic), translation (40+ languages), summarize, expand, simplify, and custom actions where you write your own prompt.

Grammar performance: 8 out of 10 errors caught. It missed the dangling modifier (only Grammarly caught that) and one comma splice, but handled everything else correctly. The grammar fix runs as a post-write action rather than real-time underlining — you type your message, tap Fix Grammar, and get the corrected version.

Tone changes were the best of the group. Five preset tones plus the ability to create custom tones means you can fine-tune exactly how your text sounds. I created a custom “Apologetic but firm” tone for a specific work situation and it nailed the voice I wanted.

Translation covers 40+ languages and works bidirectionally. You can translate your outgoing text or paste incoming text and translate it to understand it. Creating a custom “Translate to Japanese” action makes it a single tap for your most-used language pair.

The clipboard history is a standout feature that no other keyboard here offers. 100 items, pinning for frequently used items, all accessible from the keyboard without leaving your app. I covered this in more detail in the clipboard history guide.

The BYOK (bring your own key) feature lets you use your own OpenAI, Anthropic, or Google API key for AI processing. This means the AI actions run on your own account at API cost rather than using LudyType’s quota. If you use AI features heavily, this can be cheaper than any subscription — typical API costs for grammar and tone adjustments are fractions of a cent per request.

Privacy-wise, LudyType processes text locally on-device for basic operations and uses encrypted connections for AI actions. Clipboard data is stored in iOS Keychain and never leaves the device.

The $19.90 lifetime price is the most unusual part. Most AI keyboards are moving toward subscriptions, and a one-time purchase at this price point makes the math simple: it pays for itself versus any subscription alternative within a month or two.

Grammar score: 8/10 Best for: Power users who want the most features per dollar. Privacy-conscious users. Anyone tired of keyboard subscriptions.

The Comparison Table

Feature	Grammarly	SwiftKey	Gboard	CleverType	LudyType
Price	$30/mo	Free	Free	$5.99/mo	$19.90 once
Grammar accuracy	10/10	4/10	3/10	7/10	8/10
Tone change	Detect only	Via Copilot	No	Yes	Yes (5+ tones)
Translation	No	Via Copilot	Yes (100+ langs)	Yes (15 langs)	Yes (40+ langs)
Clipboard history	No	No	No	No	Yes (100 items)
Custom actions	No	No	No	No	Yes
BYOK / API keys	No	No	No	No	Yes
Swipe typing	Basic	Excellent	Good	Basic	Basic
Real-time checking	Yes	No	No	Yes	No (post-write)
Privacy model	Cloud	Cloud	Cloud	Cloud	Local + optional
Free tier	Basic grammar	Full	Full	Limited	70 actions

My Rankings

Best grammar engine: Grammarly, and it’s not close. If catching every grammatical error is your primary concern and budget isn’t a factor, nothing else matches it.

Best free keyboard: Gboard. Translate, search, GIFs, and solid autocorrect at zero cost. Hard to argue with free.

Best typing experience: SwiftKey. The swipe typing and predictions are the smoothest of the bunch. If you type a lot and want speed, SwiftKey is the fastest.

Best value for AI features: LudyType. Twenty-plus AI actions, clipboard history, custom actions, and BYOK support for $19.90 total. The math works out better than any subscription over time.

Best budget Grammarly alternative: CleverType gets you 70% of Grammarly’s grammar quality at 20% of the price. Reasonable middle ground.

The Verdict

There’s no single “best AI keyboard” because the right choice depends on what you actually need.

If you write professionally and grammar accuracy is non-negotiable, pay for Grammarly. The $30/month hurts, but the grammar engine justifies it for people whose writing quality directly impacts their work.

If you want a solid free upgrade over the stock keyboard, install Gboard. The translate feature alone makes it worth having.

If you want the most features at the best price — grammar, tone, translate, clipboard history, custom actions — LudyType at $19.90 lifetime covers more ground than any other single keyboard.

And honestly, you can have more than one keyboard installed. I currently have Gboard for casual use (the GIF search is genuinely useful in group chats) and LudyType for anything that needs AI processing. Switching between keyboards is a long-press on the globe icon.

For more specific comparisons, check out Grammarly keyboard alternatives if Grammarly’s price is your main concern, or our guides on fixing grammar on iPhone, translating text from your keyboard, and getting clipboard history on iPhone.