The one-minute tax you pay every chat

Every new ChatGPT conversation starts blank. It doesn't know your job, who reads your work, or how you like things written. So you spend the first minute of every chat re-explaining the same context, or you skip it and get a generic answer you then have to fix. Custom instructions solve this by storing that context once and applying it to every chat automatically.

What changed this month

On 15 July 2026, OpenAI raised the custom instructions limit from 1,500 characters to 5,000 for Plus, Pro, Business, Enterprise, and Education users. The old limit forced you to keep it thin. The new one is enough for a genuine profile: your role, your readers, your format rules, and the phrasing you do and don't want. This guide is the template to fill in.

Where to put it

Go to Settings → Personalisation → Custom instructions. There are two boxes: one for what ChatGPT should know about you, and one for how you'd like it to respond. Put your role and context in the first, and your format and style rules in the second. It saves automatically and applies to every new chat from then on.

A quick note on the difference from Memory

Custom instructions are separate from ChatGPT's Memory feature. Memory picks up facts on the fly as you chat. Custom instructions are the fixed profile you write deliberately. Use custom instructions for the things that are always true — your job, your audience, your rules. Let Memory handle the incidental details.

The fill-in-the-blanks profile

Copy this, replace the bracketed parts with your real details, and paste it into the two boxes. Keep it specific. Vague context produces vague answers.

ABOUT ME - Role: [your job title and what you actually do day to day] - Organisation: [industry and rough size, e.g. mid-size construction firm] - Who reads my work: [e.g. project owners, my manager, suppliers — non-technical] - Tools I use: [e.g. Outlook, Excel, Teams] HOW TO RESPOND - Language: plain Australian English spelling (organise, colour, summarise) - Length: get to the point; no long preambles - Format: short paragraphs; use a list only when I ask for one - Tone: professional but human, not stiff, no hype words - Never use: em dashes, "leverage", "unlock", "in today's world", "in conclusion" - If you're unsure of a fact, say so instead of guessing - When drafting, end with one clear next step where it makes sense
💡 Make it earn its keep

For the next week, whenever you catch yourself typing the same background into a chat, stop and add that line to your custom instructions instead. After a few days the profile does the explaining for you, and your first message can just be the actual task.

What not to put in it

Custom instructions apply to every chat, including ones where you're helping a colleague or working on something personal, so keep confidential specifics out. Store your role and preferences, not client names, financial figures, or anything you wouldn't want surfacing in an unrelated conversation. Context that shapes the writing: yes. Sensitive data: no.

Do this today

Open Settings, paste the profile above, and fill in the brackets with your real details. Then start one ordinary task the way you normally would, and notice how much context you didn't have to type. That saved minute repeats on every chat you have from now on.