Most people open ChatGPT and start every single conversation from scratch. They type their job title. Their preferred tone. Who they're writing for. Every time. ChatGPT has a feature called Custom Instructions that fixes this, and most users either don't know it exists or skip right past it.
Once you set up Custom Instructions, ChatGPT remembers who you are and how you want it to respond across every conversation automatically. No more repeating yourself.
If you've read our guide on why ChatGPT gives generic answers, you already know that context is everything. Custom Instructions are how you give ChatGPT that context permanently.
This guide shows you exactly how to find the feature, what to write in each field, and how to set it up in about 10 minutes.
What ChatGPT Custom Instructions Actually Are
Custom Instructions are a one-time setup that tells ChatGPT two things: who you are, and how you want it to communicate with you.
Once saved, those instructions apply to every new chat you open. You don't have to explain your job, your tone preference, or your audience again. ChatGPT already knows.
Think of it like briefing a new assistant on your first day together. You only do it once, you only do it once, and they never forget.
There are two fields to fill in:
"What would you like ChatGPT to know about you?" This is where you share context about yourself. Your job, your industry, who you work with, what you're trying to accomplish.
"How would you like ChatGPT to respond?" This is where you set tone, format, length, and style preferences.
Both fields have a 1,500-character limit. That's plenty. You're not writing a novel here. Just the things you'd normally have to re-explain every time.
How to Find Custom Instructions in ChatGPT
They're tucked away in settings, which is probably why so many people miss them.
On desktop (web):
- Click your profile icon or name in the bottom-left corner
- Go to Settings
- Select Customize ChatGPT (some users see Personalization depending on their version)
- Make sure Enable customization is toggled ON
- Fill in the two fields and click Save
On mobile (iOS or Android):
- Tap your profile icon or the three-dot menu
- Go to Settings then Personalization
- Toggle Enable customization ON
- Fill in the fields and save
Your instructions sync across web, desktop, and mobile automatically. Set it once on your laptop and it's already there on your phone.
What to Actually Write in the First Field
Most people leave this blank or write something like "I'm a marketer." Not useful.
The first field works best when you include your role, who your audience is, what platforms or tools you use, and any context ChatGPT would otherwise have to guess at.
Vague prompt:
I'm a marketer who uses ChatGPT for work.
Stronger version:
I'm a freelance content marketer who creates blog posts and email newsletters for B2B SaaS companies. My clients are typically early-stage startups targeting small business owners. I write mainly in English but occasionally adapt content for a European audience.
See the difference? The second version gives ChatGPT a real picture of your world. Now when you ask it to write an intro for a blog post, it already knows the industry, the audience, and the level of sophistication expected.
This ties directly into voice and tone, the things that make AI output feel generic when they're missing. Our guide on making AI write in your voice pairs perfectly with this setup step.
What to Actually Write in the Second Field
This one is about behavior. How you want ChatGPT to talk to you and format its output.
Some things worth including:
- Preferred tone (conversational, professional, direct, friendly)
- Length preference (brief vs. detailed, bullet points vs. prose)
- Things you never want to see (jargon, filler phrases, excessive lists)
- Default formatting (headers or no headers, numbered lists or paragraphs)
Before:
Be helpful and concise.
After:
Keep responses practical and direct. Skip filler phrases and motivational language. Use short paragraphs. When writing copy, avoid clichés and corporate buzzwords. Default to a conversational tone unless I ask for something formal. If I ask for a list, keep items brief with no long explanations unless I request them.
That second version will save you from editing out stiff, overwritten output every single time. Worth the 5 minutes it takes to write it.
Real Examples for Different Users
Here's what solid Custom Instructions look like for three types of users.
For a freelance copywriter:
What ChatGPT should know:
I'm a freelance copywriter specializing in email marketing and landing pages for direct-to-consumer brands. My clients sell physical products online. I write mostly for US and UK audiences aged 25-45.
How ChatGPT should respond:
Write in a punchy, conversational tone. Short sentences. Active voice. Avoid passive phrasing and academic-sounding words. Never use "utilize," "synergy," or other corporate jargon. When I ask for copy options, give me 3 variations unless I say otherwise.
For a small business owner:
What ChatGPT should know:
I run a small bakery in Austin, TX. I handle all my own marketing: social posts, email newsletters, and occasional promotions. My customers are local families and food lovers aged 25-55.
How ChatGPT should respond:
Keep things simple and warm. I'm not a marketing professional, so explain things clearly without jargon. When I ask for social posts, keep them short and friendly. We're a local business, not a corporation.
For a student:
What ChatGPT should know:
I'm a second-year university student studying business and marketing. I use ChatGPT for essay planning, research summaries, and exam prep.
How ChatGPT should respond:
Explain things clearly without being condescending. If I ask for writing help, don't write the whole thing for me. Help me improve what I have. Point out weak arguments or logic gaps. Keep explanations concise.
Each of these takes about 5 minutes to write. After that, you never have to re-explain any of it again.
Tips That Actually Make a Difference
Don't try to cram everything in. Focus on what you repeat most often. If you're constantly correcting ChatGPT's tone or format, those belong in your instructions. Everything else can stay in the individual conversation. When in doubt, leave it out. You can always add more later once you know what's actually missing.
Test right after setting up. Open a fresh chat and try something you use ChatGPT for regularly. Check if the tone and format match what you wanted. If not, head back to settings and adjust the second field. It usually just needs a small tweak.
Update them when your work changes. If you take on a new type of client or start using ChatGPT for a different purpose, update your instructions. They're not permanent. You can edit them any time.
Keep the second field honest. Don't write how you want ChatGPT to respond in an ideal world. Write what actually bothers you about how it responds right now. That's where the real value comes from.
Use them alongside good prompts, not instead of them. Custom Instructions set your baseline. They don't replace a well-written prompt for complex tasks. Think of them as the foundation, not the whole house. For those, tools like Prompt Optimizer can turn a rough idea into a detailed prompt that actually gets results.
Our prompt engineering best practices guide covers the techniques that work best alongside a solid Custom Instructions setup.
Frequently Asked Questions
Are Custom Instructions available on the free ChatGPT plan? Yes. They work on all plans: free, Plus, and Pro , across web, desktop, iOS, and Android.
Do Custom Instructions apply to every conversation? They apply to all new conversations you start after saving them. Existing chats won't be affected.
What is the character limit for Custom Instructions? Each field has a 1,500-character limit. That's enough for a solid paragraph or two per box.
Can I have different Custom Instructions for different tasks? Not directly in standard ChatGPT. If you need different setups for different projects, ChatGPT's Projects feature lets you set separate instructions per project. Otherwise you'd update your settings manually when switching contexts.
What's the difference between Custom Instructions and ChatGPT's Memory feature? Memory saves specific facts from your conversations over time. Custom Instructions set your permanent preferences and style. Both are worth using together. Think of Custom Instructions as your baseline, and Memory as the details ChatGPT picks up along the way.
If you've been typing the same context at the start of every chat: your job title, your preferred tone, who your audience is. You can stop., your preferred tone, who your audience is , you can stop. Spend 10 minutes setting up Custom Instructions, and ChatGPT will carry all of that into every conversation automatically.
It's one of the most underused features in ChatGPT. And now you know exactly how to use it.
