Best AI Tool for Email Writing (Tested & Compared)

Updated May 29, 2026

At a glance

If you’re hunting for the best AI tool for email writing, you’ve almost certainly landed on two names: Grammarly and Rytr. They’re both accessible, both have free tiers, and both get used daily for email — but they solve different problems. This comparison cuts through the marketing noise to show you exactly where each tool earns its keep, where it falls short, and which one you should actually pay for.

What We’re Actually Comparing

These two tools aren’t direct competitors in the traditional sense. Grammarly is primarily a writing assistant — it sits inside your browser, Gmail, Outlook, Google Docs, and dozens of other apps, correcting and polishing as you type. Rytr is primarily a content generator — you visit its editor, choose a template, and receive a draft. For email writing, that distinction matters enormously.

Grammarly for Email Writing

What It Does Well

Grammarly’s core strength is ubiquity and real-time feedback. The Free plan covers fundamental writing assistance — grammar, spelling, punctuation, and basic tone detection — and is a genuinely useful offering, including 100 AI prompts per month. In practice, this means Grammarly watches every email you compose inside Gmail or Outlook and quietly flags passive voice, unclear phrasing, and mismatched tone before you hit send.

The Pro plan includes all of the advanced writing features included in Premium, such as tone suggestions and full-sentence rewrites, plus team features that were previously available only in the Business plan. Those full-sentence rewrites are particularly useful for emails: Grammarly can rephrase an awkward paragraph to sound more direct, more formal, or more empathetic — depending on the tone you set.

Pro unlocks Grammarly’s full AI capabilities, including plagiarism detection, advanced sentence rewrites, and 2,000 AI prompts per month — 20x more than the Free plan’s 100 monthly prompts. For most email-heavy professionals, 2,000 prompts is more than enough for a month.

Pricing (as of May 2026)

Note: Grammarly has renamed its “Premium” plan to “Pro” — features remain the same at the same price. The Business plan is no longer available; it has been replaced with a custom-priced Enterprise plan.

Quick pricing summary: Free ($0), Pro ($12/month when billed annually at $144/year or $30/month on monthly billing), and Enterprise (custom pricing).

Free users are limited to 100 AI prompts per month — roughly 3–4 daily interactions — after which AI-powered features become unavailable until the next billing period. For regular use requiring more than occasional AI assistance, the Free tier becomes restrictive mid-month.

Real Trade-offs

Grammarly’s generative email drafting is decent but not its primary selling point. If you want to generate a full cold outreach email from scratch, Grammarly will help — but it’s slower and less template-driven than dedicated drafting tools. Its style suggestions can also be opinionated: it will frequently recommend shorter sentences in contexts where a longer, more nuanced tone is appropriate.

The bigger issue for some users: the most useful features — full-sentence rewrites, tone adjustment, unlimited AI prompts — are locked behind the $12/mo Pro plan. The free tier’s 100-prompt cap burns quickly if you’re using Grammarly for email composition rather than just proofreading.

Rytr for Email Writing

What It Does Well

Rytr’s library of over 40 templates is one of its main draws, giving you a starting point for almost any kind of short-form content. That includes email-specific templates: cold outreach, follow-ups, subject lines, and promotional emails. You paste in a brief context, pick a tone, and Rytr generates a draft in seconds. For someone staring at a blank compose window, that’s a real unlock.

The Free plan gives you 10,000 characters per month and includes access to 20+ pre-programmed tones of voice and the Chrome extension, with no credit card required. That’s enough for a handful of short email drafts per month — adequate for occasional use, not daily.

At $9 per month (or $90 annually), the Unlimited Plan allows you to generate unlimited copy in one language, 50 plagiarism checks, and priority support. That $9 entry point is genuinely the cheapest unlimited-generation plan among mainstream AI writing tools.

Pricing (as of May 2026)

Rytr offers three pricing plans: a Free plan with 10,000 characters per month, an Unlimited plan at $9/month for unlimited AI content generation, and a Premium plan at $29/month that supports 35+ languages.

By 2026, these prices have increased to $9/month (Unlimited) and $29/month (Premium) respectively — a modest increase from prior years.

Real Trade-offs

Rytr reportedly runs on GPT-3, an earlier generation AI model. This means the output can sometimes be generic and may require manual editing to add a human touch and align with a specific brand voice. For a cold email or a routine follow-up, this is workable. For a nuanced message to an important client, you’ll likely rewrite more than you use.

Rytr also doesn’t work inside your email client — you generate in Rytr’s editor, then copy and paste. If your daily writing happens across emails, Slack messages, LinkedIn updates, and docs in your browser, Rytr’s editor-first model adds friction that the pricing doesn’t account for.

What the free tier doesn’t include: plagiarism checks, custom tone matching, custom use cases, or multi-language support — Free users are locked to one language.

Head-to-Head: Best AI Tool for Email Writing

Who Should Pick Which Tool

Pick Grammarly if you write most of your own emails and need an intelligent safety net that catches tone mismatches, clunky phrasing, and grammar errors as you type. Its Gmail and Outlook integration alone justifies the $12/mo Pro plan for anyone who sends more than a dozen professional emails a day. The free tier is legitimately useful for light proofreading, though the 100-prompt cap limits AI-assisted drafting.

Pick Rytr if you need to produce a large volume of templated emails quickly — cold outreach sequences, promo blasts, follow-up drafts — and you’re comfortable doing a light editing pass before sending. Rytr earns its place at $9/month for one specific job: short-form content at scale on a tight budget. If you’re a solopreneur running email campaigns without a copywriter, Rytr gives you an affordable starting point.

The honest answer for most people: Grammarly wins the email writing use case because it lives inside your email client and improves your writing in real time, rather than requiring a separate tab. Rytr is the better pick when volume and cost are the primary constraints — not quality or polish.

Bottom line: For everyday professional email writing, Grammarly Pro at $12/mo is the stronger investment. For bulk email drafting on a shoestring budget, Rytr Unlimited at $9/mo is hard to beat.