AI email writer: the best tools in 2026

Grammarly is the AI email writer we'd install first, because it follows you. The extension sits in Gmail, Outlook on the web, your CRM and most text boxes in the browser, so the same assistant drafts a reply, rewrites a stiff paragraph or flags a tone that reads as cold. Grammarly now sells inside the Superhuman suite, and the free plan keeps the basics: spelling and grammar, a tone readout and 100 AI prompts a month. A prompt is one request ("write a polite no", "make this shorter"), so 100 covers about three requests a day.

Pro raises that to 2,000 prompts per member per month and adds full-sentence rewrites, tone adjustments and an Email Assistant that drafts replies and follows up. The price is the trap. The $12 shown on the plans page is the yearly rate ($144 a year). Pay month to month and it is $15, so $180 a year. The Pro trial costs $0 up front and Grammarly sends an email reminder 2 days before it ends: that is your window to cancel or switch to yearly.

ChatGPT is the AI email writer most people already have open. Paste the thread, say who you are writing to and what you want, and you get a draft in seconds, in any tone and in dozens of languages. The free plan is enough for most email work, because an email is short text: you rarely hit the limits that bite on images, files or deep research.

The paid tiers matter less for email than for other jobs. Go costs $8 a month in the US and may show ads. Plus is $20 a month and brings the stronger reasoning models, useful for a delicate negotiation or a long reply to a client complaint. What holds the score back is the copy and paste: ChatGPT works in its own window, so every email means switching tabs and pasting the draft back. Our full ChatGPT review details each plan, and our ChatGPT training teaches the prompting that makes drafts usable.

Claude is our pick for the emails where wording matters. It keeps your phrasing when you ask for a light edit, avoids the stock openers ("I hope this email finds you well") when you tell it to, and holds a consistent voice across a long thread. For the emails that can cost you a client, that matters more than speed.

The free plan works, but its limit resets every five hours and every week, so a heavy morning of drafting can lock you out until the afternoon. Pro costs $20 a month, or $17 a month if you pay $200 up front for the year. Claude mostly lives in its own window, so you paste the thread and copy the answer back. On paid plans, Claude for Outlook (in beta) adds a panel that drafts replies inside Outlook and leaves them waiting for you to send; the Google Workspace add-on covers Docs, Sheets and Slides, not Gmail. More in our Claude review.

MailMaestro puts the AI where you already are: a panel inside Outlook (Windows, Mac and the web) and a Chrome extension for Gmail. You click reply, pick a tone and length, add one line of intent, and the draft lands in the email. It also summarizes long threads, which is half the job when you join a conversation late.

The free plan is small. It gives 3 AI requests a week, about 156 a year, enough to test it but not to work with it. Pro costs $12 per seat a month billed yearly; month to month the 20% yearly discount disappears and you pay $15. Read the fine print before you pick yearly: annual plans aren't refundable after purchase. Free drafts carry a MailMaestro watermark, removed on Pro. And on Gmail, a few Pro features (email reminders, Ask AI about your inbox, attachment summaries) are missing: they run in Outlook only for now. Teams that also want meeting notes can bundle both products in MaestroDuo.

Gemini is built into Gmail. Open a new email or a reply, type your request in the prompt bar at the bottom (Help me write), and the draft appears in place. Three one-click options refine it: Formalize, Friendly and Shorten. It also pulls details from your other emails and Drive files, like a booking code, to personalize the reply. On a work account, Google Workspace lists Gemini in Gmail on its plans, so your team may already pay for it.

The catch is geography. On a personal Google Account, Help me write is free but restricted to the US. Elsewhere, it comes with an eligible Google AI plan: Google AI Plus at $4.99 a month, about $60 a year, which also adds Gemini in other Google apps and 400 GB of storage. Google AI Pro at $19.99 adds the stronger model. The score stays at 4 because the drafts follow a template-like shape, and the tone controls are coarser than Grammarly's. More detail in our Gemini review.

Copilot is to Outlook what Gemini is to Gmail. In a new email, click the Copilot icon, choose Draft, write a line, then adjust the length and tone. Copilot comes with Microsoft 365 Personal, Family, Premium and Pro subscriptions, which also include Word, Excel and cloud storage (1 TB on Personal).

Two price traps. Microsoft 365 Personal shows $69.99 for the first year as a limited-time offer, then renews at $99.99, so $169.98 over two years. And Copilot features in consumer plans run on AI credits: heavy use can hit the allowance. On business plans, the Microsoft 365 Copilot Business add-on is $21 per user a month billed yearly, on promotion at $18 until the end of 2026.

Lavender is an email coach more than a writer. As you type in Gmail or Outlook 365, it scores the email (aim for 90 or above), flags what hurts your reply rate and suggests fixes. It also writes drafts and pulls personalization ideas on the prospect. It plugs into Outreach, Salesloft, HubSpot, Apollo, Groove and Gong, the tools sales teams send from.

The free plan analyzes 5 emails a month, which is a demo. Starter removes the cap: $27 a month billed yearly ($324 a year) or $29 month to month ($348). Individual Pro, at $45 a month yearly, adds the sales tool integrations. For a marketer or a founder writing three emails a day, it is the wrong tool: the value is in the coaching on volume prospecting.