How to Use ChatGPT Custom Instructions (2026 Guide)

Repeating the same preferences in every ChatGPT conversation wastes time. You may keep asking for concise answers, beginner-friendly explanations, a specific writing tone, or a certain output format. ChatGPT Custom Instructions let you save those preferences once so they can shape future responses automatically.

However, useful custom instructions are not a long biography or a collection of vague wishes. They should give ChatGPT clear, reusable guidance without including private information that does not belong in every conversation.

In this guide, you will learn how to turn on ChatGPT Custom Instructions, what to write, how they differ from Memory, and how to test whether your instructions actually improve the result.

What Are ChatGPT Custom Instructions?

Custom Instructions are account-level preferences that tell ChatGPT what it should consider when responding. Instead of writing “Use plain English and give me a checklist” in every new chat, you can save that preference in your settings.

According to the official OpenAI Custom Instructions guide, the feature is available on all plans on the web, desktop, iOS, and Android. OpenAI also states that the longer text fields have a 1,500-character limit.

Custom Instructions are most useful for preferences that remain relevant across many conversations, such as:

• Your general role or experience level
• The audience you usually communicate with
• Your preferred tone and level of detail
• A response structure you use repeatedly
• Rules such as explaining jargon or identifying uncertainty

Custom Instructions vs. Memory

Custom Instructions and Memory can both personalize responses, but they serve different purposes.

Feature	Custom Instructions	Memory
Who adds the information?	You write and edit explicit guidance	ChatGPT may remember useful details from conversations
Best for	Stable rules, tone, role, and output preferences	Personal details and context that may develop over time
Control	You can directly edit or delete the text	You can review, correct, or delete saved memories
Example	“Use plain English and end with next steps.”	Remembering that you are preparing for a specific exam

Use Custom Instructions when you know exactly what guidance should apply repeatedly. Use a normal prompt when the requirement belongs only to one task. If you want ChatGPT to carry useful preferences across conversations without manually rewriting every rule, read our ChatGPT Memory guide. Custom Instructions can still affect Temporary Chat, while Memory behaves differently; our Memory vs Temporary Chat guide explains how these controls work together. If you want a dedicated workspace with its own files and instructions, read our guide to using ChatGPT Projects.

How to Turn On ChatGPT Custom Instructions

On the web or desktop app

1. Open ChatGPT and sign in.
2. Select your profile icon and open Settings.
3. Choose Personalization.
4. Open Custom Instructions.
5. Turn on customization and enter your instructions.
6. Save the changes and start a test conversation.

On iPhone or Android

1. Open the ChatGPT mobile app.
2. Open Settings.
3. Select Customize ChatGPT.
4. Enable customization and add your instructions.

Menu wording can change as the app is updated. If you do not see the option, update the app and look under Settings or Personalization.

A Reusable Custom Instructions Template

A strong setup usually covers four things: context, goals, response preferences, and boundaries. Copy the template below and replace the brackets.

I am a [role or experience level] who mainly works on [typical tasks].

My usual audience is [audience]. My main goals are [goals].

When you respond:
- Use [tone and reading level].
- Start with a direct answer, then explain the reasoning.
- Use headings, short paragraphs, and bullet points when helpful.
- Define technical terms before using them.
- State assumptions and clearly label uncertainty.
- End with practical next steps.

Do not invent facts, sources, quotes, or statistics. Ask a clarifying question when missing information would materially change the answer.

This template gives ChatGPT useful defaults without trying to control every possible conversation. Task-specific details should still go in the prompt itself. Our guide to writing better ChatGPT prompts explains how to add goal, context, audience, format, and constraints for an individual request.

Practical Example: A Small-Business Content Writer

Imagine a freelance writer who creates educational articles for small-business owners. Without Custom Instructions, the writer sends this prompt:

Give me an outline for an article about reducing meeting time.

The answer may be usable, but its tone, structure, audience, and evidence standard are undefined. The writer then adds these Custom Instructions:

I write practical educational content for small-business owners with limited time.

Use clear US English and a professional but approachable tone. Begin with the reader's problem. Use descriptive headings, short paragraphs, and actionable examples. Explain jargon. When a claim may change over time, ask for a current source or label it for verification. Never invent statistics or customer results.

After saving the instructions, the writer submits the same short request again. A better response should now:

• Frame long meetings as a time and productivity problem
• Use an outline suitable for busy business owners
• Include practical sections such as agendas, time limits, and follow-up rules
• Avoid unsupported numbers and exaggerated promises

How to interpret the result

The improved structure does not prove that every recommendation is correct. It shows that the instructions successfully influenced presentation and audience fit. The writer should still verify factual claims, add firsthand experience, and revise generic advice before publishing.

This distinction matters: Custom Instructions can improve consistency, but they do not guarantee accuracy or originality.

7 Useful Custom Instructions Examples

1. For a beginner learning a technical topic

Assume I am a beginner. Explain one concept at a time, define technical terms, and use a simple example before adding advanced detail. Ask one short check-for-understanding question at the end.

2. For professional emails

When drafting emails, use a polite and concise tone. Put the purpose in the first paragraph, make the requested action explicit, and avoid filler phrases. Do not invent names, dates, commitments, or attachments.

3. For brainstorming

When brainstorming, provide 10 distinct ideas grouped into safe, moderate, and experimental options. Briefly state the advantage and risk of each idea. Avoid repeating the same concept with different wording.

4. For decision support

When comparing options, use a table with criteria, advantages, disadvantages, cost or effort, and major uncertainties. Give a recommendation only after stating the assumptions behind it.

5. For editing your writing

Preserve my meaning and voice. Correct grammar, remove repetition, and improve clarity. Do not add facts or change claims without flagging the change. After the revision, list the three most important edits.

6. For research assistance

Separate confirmed facts, source-based claims, and your own inferences. Prefer recent primary sources. Include publication dates and direct links when web research is available. Say when evidence is missing or conflicting.

7. For action plans

Turn recommendations into a prioritized checklist. Label each step as now, next, or later. Include the expected outcome, required input, and a simple way to verify completion.

What Not to Put in Custom Instructions

Because these instructions can influence many conversations, keep them general and low-risk. Do not add:

• Passwords, security answers, or authentication codes
• Banking, payment, tax, or government identification details
• Private medical information you do not want reused
• Confidential client, employer, or project data
• Instructions to always agree with you or hide uncertainty
• Rules that encourage invented citations, fake quotes, or unsupported claims

OpenAI notes that relevant information from Custom Instructions may be provided to third-party plug-in developers when you use those plug-ins. Use only services you trust and avoid entering information you would not want shared with a connected third party.

How to Test and Improve Your Instructions

Do not judge your setup from one complicated request. Use a simple test:

1. Choose a short prompt you have used before.
2. Write down what a good response should contain.
3. Run the prompt with customization enabled.
4. Check tone, structure, audience fit, and factual caution separately.
5. Remove instructions that are ignored, redundant, or too broad.
6. Test again with a different task.

If ChatGPT keeps missing the same requirement, make it measurable. Replace “be concise” with “start with a two-sentence answer and keep each section under five bullet points.” Replace “be accurate” with “label uncertainty and do not invent sources, quotes, dates, or numbers.”

Common Problems and Fixes

The answers feel too rigid

You may have added too many formatting rules. Keep only the preferences that should apply to most conversations and move task-specific requirements into the prompt.

The instructions seem to be ignored

Confirm that customization is enabled. Simplify conflicting rules and test with a new, clear request. Also remember that safety policies and higher-priority system instructions can override personal preferences.

Every answer is too long

Specify a default length, such as “answer in 150 words unless I ask for a detailed guide.” Avoid requesting examples, alternatives, explanations, and complete checklists in every response.

The response is still generic

Custom Instructions provide stable background, not the complete context for every task. Add a specific goal, source material, audience, deadline, and output format to the current prompt. Review our list of common ChatGPT prompt mistakes for more examples.

Frequently Asked Questions

Are ChatGPT Custom Instructions free?

OpenAI says Custom Instructions are available on all ChatGPT plans. Availability and menu placement can still vary by app version, region, or managed workspace settings.

Do Custom Instructions apply to old chats?

OpenAI states that updated settings are applied immediately across chats, while previous versions can remain visible in your chat history. Test the current behavior in a new message after saving your changes.

Can I turn Custom Instructions off?

Yes. Return to Settings and Personalization, then disable customization. You can also edit or delete the text for future conversations.

Are Custom Instructions the same as a custom GPT?

No. Custom Instructions are preferences for your regular ChatGPT experience. A custom GPT is a separately configured assistant that can have its own instructions, knowledge, tools, and sharing settings. OpenAI notes that GPTs do not use your saved Memory, Custom Instructions, or previous conversations.

Can Custom Instructions make every answer accurate?

No. They can encourage careful behavior, but ChatGPT can still produce incorrect, incomplete, or outdated information. Verify important medical, legal, financial, academic, and business decisions with qualified professionals and reliable primary sources.

Final Thoughts

The best ChatGPT Custom Instructions are short enough to maintain and specific enough to test. Start with your role, typical audience, preferred response structure, and rules for handling uncertainty. Then compare the output with your expectations and revise one instruction at a time.

Use Custom Instructions for stable preferences, normal prompts for individual tasks, and Projects when you need a dedicated workspace with its own files and context. This simple separation keeps your setup useful without making every conversation feel the same.

If you are still learning the basics, begin with our step-by-step ChatGPT beginner guide.