How to Set Up ChatGPT Custom Instructions (With 10 Copy-Paste Examples)

ChatGPT custom instructions are a short note that ChatGPT reads before every reply. You write it once, and ChatGPT stops asking who you are or how you want answers. This guide shows where the setting is today, how to write instructions that work, and 10 examples you can copy and edit.

Checked in September 2026. OpenAI changes menu names and limits often, so if your screen looks different, check the OpenAI Help Center for the current steps.

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What Custom Instructions Do

Custom instructions let you tell ChatGPT two kinds of things:

• Facts about you. Your job, your level, what you are working on.
• How you want answers. Length, tone, format, and rules like "ask me a question if my request is unclear."

ChatGPT considers these instructions in your chats, so you do not have to repeat them. They are available on all plans, including the free plan, on the web, the desktop app, iOS, and Android.

A simple way to think about it, from OpenAI's own guidance: put stable preferences in custom instructions (your role, tone, formats) and put the task itself in your prompt.

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How to Set Up ChatGPT Custom Instructions

The setting now lives under Personalization. Older guides call it "Customize ChatGPT," and you may still see that name in the mobile apps.

On the web and desktop app

1. Click your profile icon and open Settings.
2. Select Personalization.
3. Make sure Enable customization is turned on.
4. Type your instructions in the Custom Instructions field.
5. Save.

On iPhone and Android

1. Open Settings from your profile icon.
2. Select Customize ChatGPT (on some app versions this is labeled Personalization).
3. Turn on Enable customization.
4. Type your instructions in the Custom Instructions field.

Turning them off

Go back to the same screen and switch Enable customization off. You can also delete the text. OpenAI says changes apply right away. For a clean test, start a new chat after you edit your instructions.

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Character Limits by Plan

Plan	Custom instructions limit
Free and Go	Up to 1,500 characters
Plus, Pro, Business, Enterprise, and Education	Up to 5,000 characters

1,500 characters is about 250 words. That is enough for most people if you write clearly. Every example below fits inside the free limit.

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Other Settings on the Personalization Screen

The Personalization screen has more than the text box. These settings work together with your custom instructions.

Base style and tone

This dropdown sets ChatGPT's overall personality. The options are Default, Professional, Friendly, Candid, Quirky, Efficient, and Cynical. For example, Efficient gives short, direct answers, and Professional uses formal, polished language. The personality changes how ChatGPT sounds, not what it can do.

Characteristics

Characteristics let you push a few traits up or down: Warm, Enthusiastic, Headers & Lists, and Emojis. If you want fewer bullet points or no emojis, this is a quicker fix than writing it in your instructions.

Tip: use the dropdown and characteristics for tone. Use the custom instructions box for things only you know, like your job, your audience, and your rules.

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Custom Instructions vs Memory vs Projects

These three features overlap, and people mix them up. Here is how they differ.

Feature	What it is	Who writes it	Where it applies
Custom instructions	Your standing rules and background	You	Your chats in general
Memory	Details ChatGPT saves from your chats, or that you ask it to remember	ChatGPT, and you	Your chats, when Memory is on
Project instructions	Rules for one project only	You	Chats inside that project

A few details from OpenAI's help pages:

• Project instructions win inside a project. They apply only to that project and override your general custom instructions. This is useful when one project needs a different tone. See our guide on how to use ChatGPT Projects.
• Shared projects do not use your personal instructions. If you share a project with others, it does not use your custom instructions or memories.
• Memory can read your custom instructions. Memory can draw on several sources, including past chats, saved memories, and custom instructions. You can manage it in Settings > Personalization > Memory. Our post on ChatGPT memory prompt injection explains why it is worth checking what is saved there.
• Temporary chats can skip them. Before you start a temporary chat, you can pick Unpersonalized to leave out your memories and custom instructions.

Custom instructions are also not the same as custom GPTs. A custom GPT is a separate assistant you build for one job. If that is what you want, see our list of custom GPT ideas.

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What Makes a Good Custom Instruction

Most weak instructions are vague. "Be helpful and concise" changes almost nothing, because ChatGPT already tries to do that. Good instructions are specific and checkable. You should be able to look at a reply and say yes or no: did it follow the rule?

Vague	Specific and checkable
Keep it short	Answer in 150 words or less unless I ask for more
Use simple language	Use words a 15-year-old would know. Explain any technical term in one sentence
Be accurate	If you are not sure about a fact, say so. Do not invent sources or numbers
Format nicely	Use a short list for steps. Use a table when I ask to compare things
Understand my level	I am a beginner in Excel. Do not assume I know formulas beyond SUM

A few more rules that help:

1. Say who you are in one or two lines. Role, level, and what you use ChatGPT for.
2. Say who the answers are for. Your boss, your students, your customers.
3. Add one or two "do not" rules. For example, "Do not start with praise for my question."
4. Tell it what to do when it is unsure. "Ask me one clarifying question first" saves a lot of back and forth.
5. Keep it short. Long lists of rules can conflict. Ten clear lines beat forty fuzzy ones.
6. Test and adjust. Ask three normal questions, see what it gets wrong, and fix that one line.

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10 ChatGPT Custom Instructions Examples

Copy one, replace the parts in [square brackets], and paste it into the Custom Instructions field. Each one is under 1,500 characters.

1. Student

I am a [year/grade] student studying [subject]. I use ChatGPT to understand topics and check my work, not to write my assignments.
- Explain ideas step by step, starting simple.
- Give one short example for every new idea.
- When I share my answer, point out mistakes but let me fix them first. Give hints before full solutions.
- End long explanations with 3 quick questions to test me.
- If a fact might be wrong or out of date, tell me to check it in my textbook or a trusted source.

2. Teacher

I teach [subject] to [age group/grade] students. I use ChatGPT to plan lessons, write questions, and explain topics simply.
- Match reading level to my students' age.
- For lesson plans use: goal, warm-up, main activity, check for understanding, homework.
- For quizzes, include the answer key at the end, with a one-line reason for each answer.
- Suggest one low-cost activity that needs no technology.
- Do not invent facts, dates, or quotes. Mark anything I should double-check.

3. Marketer

I work in marketing for [company type] that sells [product/service] to [audience].
- Write in plain, friendly language. No hype words like "revolutionary" or "game changer".
- For any copy, give 3 options: short, medium, and long.
- Always state the one main benefit in the first line.
- For social posts, follow each platform's normal length and style.
- If I ask for ideas, rank them by how easy they are to test this week.
- Do not make up statistics or customer quotes.

4. Developer

I am a [level] developer working mainly with [languages/frameworks].
- Show code first, then a short explanation.
- Use current, stable versions of libraries. Say which version you assume.
- Add types and handle errors. Skip obvious comments.
- When you change existing code, show only the changed parts and say where they go.
- If there are two good approaches, name both in one line each and pick one.
- If you are not sure an API or function exists, say so instead of guessing.

5. Job seeker

I am looking for a job as a [target role] in [industry]. I have [X] years of experience in [field].
- Help me with resumes, cover letters, and interview practice.
- Use action verbs and real results. Never invent numbers or experience I do not have. Ask me for the facts instead.
- Keep resume bullets to one line each.
- For interview practice, ask one question at a time, wait for my answer, then give feedback: one strength and one fix.
- Keep a confident but honest tone.

6. Small business owner

I run a small [type of business] with [number] staff. My customers are mostly [customer type]. I have little time and a small budget.
- Give practical steps I can do this week.
- Prefer free or low-cost tools. Say the cost if a tool is paid.
- For emails and messages to customers, keep them short and polite.
- When I ask about money, tax, or legal topics, give general guidance and tell me when to check with a professional.
- Use simple words. No business jargon.

7. Writer

I write [type of writing, e.g. blog posts / fiction / newsletters] for [audience].
- When I ask for edits, keep my voice. Do not rewrite everything.
- Show changes as a short list of suggestions before giving a full new version.
- Prefer short sentences and active voice.
- Point out weak openings, repeated words, and unclear sentences.
- Do not add clichés or filler phrases.
- If I ask for ideas, give 5, each in one line.

8. Non-native English speaker

English is my second language. My first language is [language]. My level is [beginner/intermediate/advanced].
- Use simple English and short sentences.
- When you use a less common word, add a simple meaning in brackets.
- When I write in English, correct my mistakes at the end of your reply. Show my sentence, the correct sentence, and a short reason.
- If I write in [language], answer in [language] unless I ask for English.
- Do not use idioms or slang unless I ask.

9. Researcher

I am a researcher in [field] at [level, e.g. PhD / industry]. I use ChatGPT to explore ideas, summarize papers, and plan analyses.
- Separate what is well established from what is debated or uncertain.
- Do not invent citations. If you mention a source, tell me to verify it. If you cannot name a real one, say so.
- For summaries use: question, method, main findings, limitations.
- Point out weak points in my reasoning.
- Use precise terms from my field but define anything unusual.

10. Busy parent

I am a parent of [number] kids aged [ages]. I have little free time.
- Keep answers short and practical. Give the answer first.
- For meal ideas, use common ingredients and 30 minutes or less. Note common allergens.
- For activities, suggest things that need little setup and little money.
- When I ask for help explaining something to my kids, give me simple words for their age.
- For health questions, give general information and tell me when to call a doctor.

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Common Problems and Fixes

ChatGPT ignores one of my rules. Make the rule more specific and move it higher up. "Answer in 150 words or less" works better than "be brief."

Answers feel too stiff or too chatty. Change Base style and tone or the Characteristics instead of adding more text.

One task needs different rules. Put those rules in a project instead. Project instructions override your general ones inside that project.

I hit the character limit. Cut adjectives and repeated ideas. Keep only rules that change the answer. On the free plan, aim for eight to ten short lines.

I do not want my instructions used in a chat. Start a temporary chat and choose Unpersonalized, or turn off Enable customization for a while.

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Frequently Asked Questions

Where are custom instructions in ChatGPT now?

On the web and desktop app, go to Settings, then Personalization, turn on Enable customization, and use the Custom Instructions field. On iPhone and Android, open Settings and look for Customize ChatGPT or Personalization.

Are ChatGPT custom instructions free?

Yes. OpenAI says custom instructions are available on all plans, including the free plan, on web, desktop, iOS, and Android.

How long can ChatGPT custom instructions be?

Free and Go users can save up to 1,500 characters. Plus, Pro, Business, Enterprise, and Education users can save up to 5,000 characters.

What is the difference between custom instructions and memory?

Custom instructions are rules and background you write yourself. Memory is information ChatGPT saves from your chats, or that you ask it to remember. Memory can also draw on your custom instructions. You manage both under Personalization.

Do custom instructions work inside ChatGPT Projects?

Project instructions apply only inside that project and override your general custom instructions. Shared projects do not use your personal custom instructions or memories.

Can people see my custom instructions if I share a chat?

No. OpenAI says your instructions are not shared with people who view a shared chat link.

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Want to go further? Custom instructions are one part of a bigger skill: giving AI the right context. Our free Context Engineering course shows how to control what the AI sees so you get better answers. For more everyday ChatGPT skills, try ChatGPT Power User.