If you’re anything like me, you probably spend a decent chunk of your working day staring at a half-written email, wondering whether your opening line sounds too abrupt, too grovelling, or just plain weird. Professional email writing is one of those skills nobody really teaches you, and yet getting it wrong can quietly damage how you’re perceived at work. I’ve lost count of the times I’ve rewritten the same three sentences because they just didn’t sound right. Then AI tools came along, and honestly, they changed the way I approach work communication entirely. But here’s the thing: used badly, AI emails are immediately obvious. Stiff, over-formal, full of phrases like “I hope this email finds you well” and “please do not hesitate to reach out.” Painful stuff.
The good news is that with the right approach, you can use AI to write emails that are sharper, clearer, and faster to produce, while still sounding like you. This guide will show you exactly how to do that using ChatGPT and Claude, including the prompts that actually work, how to keep your own voice in the process, and the few situations where you should absolutely be writing it yourself.
Before You Start
You don’t need a paid subscription to try either tool. Both ChatGPT and Claude have free tiers that are perfectly usable for email drafting. ChatGPT’s free plan runs on GPT-4o Mini, which handles conversational and professional writing well enough for most tasks. Claude’s free tier gives you access to its Sonnet model, which is arguably the stronger option for writing specifically, though message limits do kick in during busy periods. If you find yourself using these tools daily, Claude Pro runs at around £16 per month and ChatGPT Plus at around £20 per month, though always check the current pricing at checkout as both services bill in USD and UK prices are subject to VAT and exchange rate changes. For most people, the free tiers are a perfectly sensible starting point.
Step 1: Understand Which Tool Does What
Before you start prompting, it helps to know which AI is better suited for email work, because they’re genuinely different.
ChatGPT is the bigger name, with around 800 million monthly active users globally as of late 2024. It’s excellent at generating drafts quickly, handling structured tasks, and working across a wide range of formats. The downside for writing is that it can lean towards over-polished, slightly corporate language. It also has a persistent habit of drifting back to American spellings even if you tell it to write in British English, so you’ll need to nudge it regularly.
Claude, from Anthropic, is the one I reach for when the email actually matters. It’s designed with a stronger emphasis on natural language quality, and it shows. Claude is noticeably better at matching tone, avoiding buzzword-heavy filler, and following complex instructions without losing the thread. If you tell Claude to write something that sounds like a direct but friendly manager, it’ll nail it. ChatGPT will sometimes give you a manager who sounds like they’ve just completed a corporate communications workshop.
The best real-world approach is to use both together. ChatGPT for speed and exploration, Claude for refinement and anything that needs to sound genuinely human. Think of it as a two-pass process.
Step 2: Build a Prompt That Actually Works
This is where most people go wrong. Typing “write me an email to my boss” into an AI chatbot will get you something generic and useless. The key is giving the AI enough context to do the job properly.
A solid email prompt needs four things:
1. Your role and theirs. Tell the AI who you are and who you’re writing to. Not just job titles, but the relationship. “I’m a project manager writing to a client we’ve worked with for two years. Friendly but professional relationship.”
2. The purpose of the email. Be specific. “I need to push back the deadline on a deliverable by one week, explain why, and reassure them it won’t affect the final outcome.”
3. The tone you want. Don’t just say “professional.” Say “direct but warm,” or “confident without being pushy,” or “apologetic but not grovelling.” Adjectives matter here.
4. Any specific details or facts to include. Bullet these out. The AI can weave them in so you don’t have to.
Here’s an example of a prompt that works:
“Write a professional email from a senior developer to a non-technical client. We’re delaying a feature release by five days because of an unexpected server migration issue. The tone should be calm, confident, and reassuring. Keep it under 150 words. British English. Include: the delay, the reason (brief, non-technical), what we’re doing to stay on track, and a note that their account manager will be in touch to discuss impact.”
Compare that to “write an email about a delay.” Night and day.
Step 3: Keep Your Voice in the Output
This is the bit most guides skip over, and it’s the most important part if you want emails that actually sound like you.
The most effective technique is to feed the AI examples of your own writing first. Paste in two or three emails you’ve written that you’re happy with, then say: “This is how I write. Keep this tone and style when drafting the email I’m about to describe.” Claude handles this particularly well. It’ll absorb the rhythm of your sentences, your level of formality, and even your tendency to use short paragraphs or longer explanatory ones.
Another approach is to write a rough first draft yourself, even a bad one, then ask the AI to improve it rather than replace it. Tell it what’s wrong: “This sounds too stiff, can you make it more conversational while keeping the key points?” You stay in control of the content and the ideas. The AI just helps you express them better.
Always read the output aloud before sending. If there’s a phrase you wouldn’t say in a meeting, cut it. Phrases like “as per my previous communication,” “moving forward,” and “synergies” are red flags that the AI has gone rogue.
Step 4: Know What to Never Let AI Write
This is non-negotiable. There are categories of email that AI should not be writing for you. Full stop.
Anything involving a disciplinary matter or HR situation. These require careful human judgement, legal awareness, and genuine empathy. A badly worded AI draft could cause serious problems.
Sensitive personal apologies. If you’ve genuinely made a mistake that’s affected someone, that email needs to come from you. An AI apology is often detectable, and being found out is far worse than the original error.
First impressions to important new contacts. A quick AI draft is fine as a starting point, but don’t send it unedited. Your first email to a potential employer, a major new client, or a senior contact you’ve never met should have genuine human thought behind every line.
Anything containing confidential business information. Before you paste sensitive data or internal details into any AI chatbot, check your employer’s policy. Many companies have restrictions on what can be submitted to third-party AI services, and with good reason.
Step 5: Refine, Don’t Just Accept
Always treat the AI output as a first draft, not a finished product. Go back and ask follow-up questions: “Can you make the opening line stronger?” or “The second paragraph is too long, can you tighten it?” You can iterate quickly, and the result will be noticeably better than the first pass.
If you’re using Claude, try asking it to give you two or three versions with slightly different tones. Then pick the best bits from each. That combination of options is genuinely useful when you can’t quite decide how formal to pitch something.
If It’s Still Not Working
The output sounds generic despite a detailed prompt. Try adding more personality cues. Tell the AI specific things to avoid, not just what to include. “Don’t use ‘hope this finds you well’ or any variation of it” goes a long way.
It keeps reverting to American spelling. With ChatGPT this is a known issue. Add “British English throughout, including spellings like colour, behaviour, and organise” to every prompt, not just the first one in a conversation.
The email is too long. Give the AI a firm word limit upfront. “Under 120 words” is more effective than “keep it concise.”
Wrapping Up
Used properly, AI makes you a significantly better email communicator. Not by writing for you, but by getting you out of your own head and onto the page faster. The prompts, the voice-matching technique, and the two-tool approach outlined above should give you everything you need to get started today. If something’s still not clicking, drop a comment on the article or bring the question to the newsletter community where there are plenty of people working through the same thing.
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