AI Email Writer: Gmail, Outlook and ChatGPT Compared

Nobody needs AI to write "sounds good, see you at 4". The emails worth handing over are the ones that sit in drafts for two days: the follow-up on an unpaid invoice, the apology for a missed deadline, the cold pitch, the one where you're annoyed and shouldn't show it.

For those, an AI email writer is genuinely useful. It gets you past the blank screen, and it strips out the sentence you'd regret. Here's what each option costs and how to get email that doesn't read like a template.

What you can use, and what it costs

Option	Where it works	Who has it
Gmail "Help me write"	Inside Gmail	Workspace business plans, Google AI Plus/Pro/Ultra, and free in personal accounts in the US
Outlook Copilot	Inside Outlook	Microsoft 365 plans with a Copilot licence
ChatGPT, Claude	A separate tab	Free plans available
Grammarly	As you type, in the browser	Free plan for grammar and clarity

Gmail. Google's "Help me write" appears in the compose window and drafts from a short instruction, with options to make a draft shorter, longer or more formal. It comes with Workspace Business and Enterprise plans and with Google AI Plus, Pro and Ultra subscriptions; personal accounts in the US have had it at no charge. If you don't see the pencil icon in compose, your account doesn't include it.

Outlook. Copilot in Outlook drafts replies and summarises long threads, but it needs a Microsoft 365 plan with Copilot. Business users usually get it through their employer.

A chatbot in another tab. This is the most flexible option and costs nothing. You paste the context you're willing to share and get a draft you edit. It's also the only one of the four where you fully control what gets sent to the model.

The prompt that produces a sendable draft

The difference between useful and useless output is how much you put in. Most people write "write an email asking for payment" and get something generic.

Give it five things: who you're writing to, your relationship, what happened, what you want, and the tone.

"Write a short email to a client who hasn't paid an invoice due 18 days ago. We've worked together for two years and I want to keep the relationship. I want payment this week or a date I can rely on. Polite, direct, no guilt-tripping, under 120 words. Plain English, no corporate phrases."

Then do the two things that make it yours:

1. Rewrite the first line. AI openers are the most recognisable part. "I hope this email finds you well" is the tell.
2. Cut a third. Models over-explain. The shorter version almost always lands better.

Four emails worth giving to an AI email writer

The chase. Overdue invoices, unanswered proposals. AI is good at firm-but-warm, which is hard to write when you're frustrated.

The bad news. A delay, a price increase, a no. Ask for a version that leads with the decision and gives one reason, without over-apologising.

The cold email. Ask for three different openings rather than one email, then pick the one that sounds like you.

The one you wrote angry. Paste your draft and ask: "Keep every fact and the firmness, remove anything that sounds personal or sarcastic." This single use saves more relationships than all the drafting features combined.

What not to put in

An email often carries exactly the information you shouldn't paste into a personal AI account:

• Client names, contract terms, pricing and unreleased plans. Describe the situation generically: "a client", "an overdue invoice", "a mid-five-figure amount".
• Anything personal about someone else. Health, performance reviews, disputes.
• Entire threads. If you want a summary, remove names and identifying details first, or use the business account your employer provides, which carries stronger data commitments.

The built-in assistants in Gmail and Outlook have an advantage here: with a business plan, the content stays inside an account your organisation controls.

Writing for Indian business email

A few habits specific to how business email works here:

• Get the greeting right. "Dear Sir/Madam" still reads as correct to many recipients; "Hey" doesn't. If in doubt, use the person's name.
• Say the ask in the first two lines. Long preambles get skimmed.
• Give a date, not "at the earliest". "By Friday 17 October" avoids a second email.
• Match the channel. If the relationship runs on WhatsApp, a sudden formal email reads as escalation. Sometimes that's what you want; know which you're doing.
• Watch Americanisms. Models default to US phrasing and spelling. Ask for Indian or British English if that's your house style.

Keep a draft folder of your own voice

The most useful thing you can do is build a small file of five emails you've written that worked: a chase, a pitch, a no, an apology, a thank-you. Paste one in as a style example when you ask for a new draft. The output will sound like you instead of like everyone else, which is the entire problem with AI email in the first place.

For more in this category, see our AI writing tools ranking and the free AI writing tools list.

FAQ

Is Gmail's Help me write free?

It depends on your account. It comes with Google Workspace business plans and Google AI Plus, Pro and Ultra subscriptions, and has been available at no charge in personal accounts in the US. If the icon isn't in your compose window, your plan doesn't include it.

Do I need Copilot to use AI in Outlook?

For the built-in drafting and thread summaries, yes: Outlook's Copilot features require a Microsoft 365 plan with a Copilot licence. Otherwise use a chatbot in a separate tab and paste the draft in.

How do I make AI email sound less robotic?

Rewrite the opening line yourself, cut the draft by a third, and give the assistant one of your own past emails as a style example. Ban stock phrases like "I hope this email finds you well" in the prompt.

Is it safe to paste work emails into ChatGPT?

Not with client names, pricing or confidential plans in a personal account. Describe the situation generically, or use a business account whose data terms your employer has accepted.

What is the best free AI email writer?

ChatGPT or Claude on their free plans, with Grammarly's free checks for a final pass. Both give you more control over tone than the built-in buttons, and neither needs a paid subscription.