Tired of reminding ChatGPT that you like short answers, that you want a professional tone, that you teach high school math, or that you don’t want bullet points everywhere? That’s exactly what custom instructions are for: a setting you fill in once, and ChatGPT applies it to every conversation from then on.
It’s probably the highest-payoff setting in ChatGPT, and yet one of the least used. In this guide, I’ll show you where to find custom instructions, how to write them, and which examples actually work for different profiles, plus how to combine them with memory and projects. If you’re just getting started, my complete ChatGPT guide covers the basics.
Key takeaways
- Custom instructions tell ChatGPT who you are and how it should respond, in all your conversations.
- You set them in Settings → Personalization, including on the free plan.
- You can also set a base style and tone and a few characteristics (warmth, enthusiasm, formatting, emojis).
- Keep it short and specific: a few well-chosen lines beat a full page.
- For a specific topic, use project instructions instead, which only apply to that project’s chats.
Information checked on September 29, 2026.
Contents
- What are custom instructions for?
- Where to find custom instructions
- How to write good instructions
- 6 custom instruction examples for different profiles
- Base style and tone
- Custom instructions, memory and projects: how to combine them
- Test and improve your instructions
- Before and after: what instructions actually change
- The most common mistakes
- Instructions for work
- The limits of custom instructions
- Privacy
- FAQ
- The bottom line
What are custom instructions for?
Without instructions, ChatGPT answers everyone the same way, in its default style: often long, packed with lists, polite and a bit generic. With custom instructions, it knows right away:
- who you are: your job, your skill level, your interests, your situation;
- how to respond: length, tone, format, casual or formal;
- what to avoid: filler phrases, emojis, overly cautious answers, jargon.
In practice, it’s like handing a new assistant a profile sheet, once and for all. Every conversation benefits immediately.
Where to find custom instructions
- Click your name or profile picture.
- Open Settings.
- Go to the Personalization section.
- There you’ll find your custom instructions along with other personalization options. The exact layout of the fields varies depending on the interface, but there are always two main parts: what ChatGPT should know about you and how it should respond.
Changes take effect immediately, including in existing conversations.
How to write good instructions
The “about you” part
Share the information that actually changes the answers. No need for your life story: three to six lines are plenty.
- Your work: “I’m a home health nurse in a rural area.”
- Your level in the areas you ask about: “Beginner with computers, comfortable with numbers.”
- Your context: “I have two kids, ages 7 and 12, and I live near Austin, Texas.”
- Your main uses: “I mostly use ChatGPT for letters and emails, family logistics and studying for my continuing education credits.”
The “how to respond” part
This is where most of the magic happens. Be precise and concrete:
- Length: “Short answers by default; only go into detail if I ask.”
- Tone: “Direct and warm, no canned phrases.”
- Format: “Paragraphs rather than lists, except for steps.”
- Language: “Always answer in English, even if I paste in text in another language.”
- Habits: “Ask me a question if my request is unclear. Tell me when you’re not sure.”
What to avoid
- Instructions that are too long: past fifteen lines or so, they start contradicting each other or getting partly ignored.
- Vague directions: “Be smart” or “Give good answers” won’t change a thing.
- Sensitive information: no phone number, exact address, detailed health information or banking details.
- Impossible rules: “Never make a mistake” guarantees nothing. Go with “Flag anything that should be double-checked” instead.
6 custom instruction examples for different profiles
Here are complete examples to copy and adapt. Each one includes both parts.
For everyday personal use
About me: 45, two teenagers, I work in local government. I use ChatGPT for letters and emails, family planning, recipes and everyday paperwork. How to respond: short, practical answers in a simple, friendly, casual tone. Give me the solution first, then details only if I ask. For anything involving official paperwork, remind me to double-check on the official website.
For a freelancer
About me: freelance graphic designer; my clients are mostly local shops and restaurants. I need help with quotes, client emails, social media posts and running my business. How to respond: in anything written for clients, use a professional but warm tone, with no marketing jargon or superlatives. Always give me two versions when you write something for a client.
For a student
About me: sophomore psychology major in college. I use ChatGPT to understand my classes, study and organize my papers. How to respond: explain with concrete examples and precise vocabulary. Don’t do my homework for me: guide me with questions. For scientific references, tell me clearly if you’re not sure a source actually exists.
For a manager
About me: I manage a team of 12 people in logistics. I use ChatGPT to prepare meetings, write team messages and think through decisions. How to respond: get straight to the point, start with the recommendation, then the reasoning. Anticipate possible objections. Use a table when I’m comparing options.
For a senior who’s just starting out
About me: 72, retired, just discovering ChatGPT. I’m not comfortable with computers. How to respond: short sentences, simple words, no tech jargon. Explain the steps one at a time and ask me whether it worked before moving on to the next one. Keep a polite, respectful tone.
For learning a language
About me: intermediate (B1) Spanish; I’m getting ready for a six-month stay in Seville. How to respond: when I write in Spanish, answer in simple Spanish and correct my mistakes at the end of your reply, in English. When I write in English, answer in English.
Base style and tone
On top of written instructions, ChatGPT offers a base style and tone setting, plus characteristics that let you adjust things like warmth, enthusiasm, formatting and emoji use. These settings work alongside custom instructions and memory.
They’re handy for a quick tweak, but written instructions are still more precise. You can combine the two: a base style, fine-tuned by your instructions.
Custom instructions, memory and projects: how to combine them
These three tools complement each other:
| Tool | Who writes it? | Applies to | Best for |
|---|---|---|---|
| Custom instructions | You | All conversations | Your fixed rules: who you are, how to respond |
| Memory | ChatGPT (and you) | All conversations, if turned on | What builds up over time as you chat |
| Project instructions | You | That project’s conversations | A specific topic with its own rules |
My rule: custom instructions for what doesn’t change, memory for what evolves, and projects for what’s specific. I go into detail on memory in my article on ChatGPT memory, and on projects in my guide to ChatGPT projects.
If your general instructions and a project’s instructions contradict each other (say, “short answers” on one side and “detailed answers” on the other), the project instructions win inside that project.
Test and improve your instructions
Instructions are never perfect on the first try. Here’s my method:
- Write a short first draft.
- Ask three of your usual questions (the settings apply immediately).
- Notice what doesn’t work for you: too long, too formal, too many lists?
- Tweak one instruction at a time, then test again.
- Review your instructions every three months: your situation changes, and they should keep up.
And to save time, ask ChatGPT to help you write them:
Ask me about ten questions about myself, how I use ChatGPT and how I like answers to be. Then write my custom instructions in two parts (“about me” and “how to respond”), 120 words max in total, ready to paste into settings.
Before and after: what instructions actually change
To see the difference, I asked the same question before and after setting my instructions: “How can I lower my electric bill this winter?”
Without instructions, I got a long list of fifteen generic tips, split into five categories with bold headings, an intro and a conclusion. It was all accurate, but a lot of it didn’t apply to me: I live in an apartment with central heating included in the building.
With my instructions (“I live in a 650 sq ft apartment in Chicago with central building heat. Short answers, most effective tips first, in paragraphs”), the answer was six lines long, focused on what I could actually change: hot water, devices on standby, the washing machine, lighting. Plus one sentence pointing out that building heat is something to raise with the building management or HOA.
That’s the real power of custom instructions: same question, an answer tailored to your life, without having to re-explain your situation every time.
The most common mistakes
Here are the mistakes I see most often when people send me instructions that “don’t work”:
- Hedging everything: “I’d maybe like slightly shorter answers if possible.” Be assertive: “Short answers.”
- Mixing up the two parts: putting response rules in “about you,” and vice versa. Each field has its job.
- Copying someone else’s instructions without adapting them: they describe a different person with different needs.
- Forgetting to update them: a new job, a move or a change in your family situation should show up there.
- Trying to plan for everything: special cases are better handled in the conversation or in a dedicated project.
A good test: read your instructions out loud. If you couldn’t explain them in thirty seconds to a new human assistant, they’re too complicated.
Instructions for work
If you use ChatGPT for work, a few extra instructions make a real difference:
- Your industry’s vocabulary: “Use construction terminology, I’m a site superintendent.”
- Who you usually write to: “My messages are mostly for homeowners, not industry professionals.”
- Your brand guidelines: “No slang, no exclamation points, never promise a deadline.”
- Your quality bar: “Flag any information that should be verified before it goes to a client.”
Heads-up: on a work account (Business or Enterprise plans), your organization may set its own rules. And whatever your plan, never put confidential information about your clients or your company in there.
The limits of custom instructions
- They’re not always followed 100%: on a very different request, ChatGPT may drift from them. Restate the instruction in the conversation if needed.
- They don’t guarantee accuracy: telling it to “never be wrong” doesn’t prevent mistakes.
- Too many rules dilute them all: the more you add, the less each one carries.
Privacy
Custom instructions are saved to your account and used in every conversation. Only put in what you’d be happy to print on a business card: your job, your level, your preferences. Avoid sensitive information. When you start a Temporary Chat, you can choose “Personalized” or “Non-personalized.” A non-personalized Temporary Chat uses neither memory, nor custom instructions, nor plugins; a personalized Temporary Chat can use them, but it doesn’t create or update memories.
FAQ
Are custom instructions free?
Yes, they’re available on every plan, including the free one. See my article on free ChatGPT.
Do custom instructions work on mobile?
Yes, they’re tied to your account and apply on the website, the desktop app and the mobile apps.
Can I have multiple sets of instructions?
Not for your general instructions, but projects let you use different instructions for different topics. That’s the way to separate personal and work use.
Why isn’t ChatGPT following my instructions?
Check that your instructions don’t contradict each other, that they’re specific enough, and that a project isn’t imposing different instructions. Shorten them if they’re very long.
How is this different from memory?
You write the instructions, and they don’t change on their own. Memory is something ChatGPT builds up as you chat, under your control.
Can I turn off my instructions temporarily?
Yes. You can edit or clear them anytime in settings, and changes apply right away. For a single conversation without personalization, use a “Non-personalized” Temporary Chat: your instructions stay in place for everything else.
The bottom line
Custom instructions are the highest-payoff setting in ChatGPT: a few lines saying who you are and how you want it to respond, and every conversation gets more useful. Keep them short and specific, test, tweak, and combine them with memory and projects.
To go further, learn how to write a good prompt and check out 10 useful ChatGPT prompts for everyday life.
