AI Prompt Optimizer
Improve your prompts in 1 click
Got a prompt that's not giving the result you want? Paste it below: the optimizer rewrites it, adding the expected result, useful context and output format it was missing. Iterate as many times as you want. 100% free, no signup.
Starting from scratch?
If you don't have a prompt to improve yet, use our Builder to assemble a prompt step by step (role, context, instruction, format).
Before/After examples
Here are 3 examples of prompts optimized by our tool to give you an idea of the expected result.
Before
Write an email to a customer
After
Write a professional and warm follow-up email to a customer who hasn't replied to our quote for 7 days. Format: catchy subject (max 10 words), 3 short paragraphs (250 words max), clear call-to-action at the end. Tone: empathetic, no sales pressure.
Before
Summarize this article
After
Summarize the following article for an audience of busy executives. Format: 1 hook sentence, 3 bullet points with key insights, 1 actionable conclusion. Maximum 150 words. Keep only key figures and essential proper nouns. Do not rephrase the author's opinions, paraphrase them.
Before
Give me LinkedIn content ideas
After
Propose 10 LinkedIn post topics for [PROFESSION] aiming to attract [TARGET PERSONA]. Format: markdown table with columns "Angle", "Hook (first sentence)", "Post type" (storytelling / list / opinion / question), "Goal" (engagement / lead / authority). Mandatory mix: 4 storytelling, 3 actionable lists, 2 sharp opinions, 1 open question.
How to optimize a prompt effectively
A prompt that works relies on five levers, which you can also apply by hand. The optimizer always spells out the expected result, the context and the format. It adds a role or an example only when they serve the answer:
- 1
An expert role
Only when it changes the answer, the prompt states who answers ("As a senior copywriter…"). A lawyer and a salesperson don't write the same follow-up email.
- 2
Precise context
We add the target audience, the goal and the project constraints. The less the AI has to guess, the more accurate the answer.
- 3
Structured instructions
The request is broken into clear directives instead of a vague sentence: one idea per instruction.
- 4
A defined output format
Table, bullet points, word count, sections: we state exactly what the answer should look like.
- 5
Constraints and advanced techniques
Tone, length and style, plus an example when it clarifies the expected result. No need to ask the AI to write out its reasoning step by step. For a hard problem, adjust the thinking level of your app instead, when it offers one.
Go further
To go further, read our guide on how to optimize your AI prompts and the anatomy of a perfect prompt, learn to prompt Claude effectively, or grab ready-to-use templates from our free prompt library.
What the new models change
Anthropic, OpenAI and Google have published new prompting guides for their latest models. We went through them in October 2026, and the optimizer changed on three points, whichever target model you pick:
It no longer asks the model to write out its reasoning step by step. Claude Fable 5.1 may decline that request, and Google says it is generally unnecessary with Gemini 3. To see how the model reached its answer, ask it for a short explanation instead.
It writes simple instructions, without capitals for emphasis. The Gemini 3 guide notes that the model responds best to direct instructions and may over-analyze long techniques built for older models.
When your prompt doesn't say what the answer should look like, it adds length, structure and tone. All three guides ask you to specify the expected format or structure.
A tip for your own settings: with Claude Opus 5.5, the "think carefully before answering" line can come out of your custom or project instructions. The model decides how much to think, and the effort level stays the main control.
The “Target model” menu also adds the guidelines published by the brand you pick. The details are on the ChatGPT Prompts, Claude Prompts and Gemini Prompts pages.
Frequently asked questions
How does the prompt optimizer work?
You paste your prompt in the textarea, click "Optimize with AI", and our AI spots what is missing, such as the expected result or the output format, then rewrites an improved version in a few seconds. You can iterate multiple times on the result.
Is the prompt optimizer free?
Yes, 100% free and no signup. You can run up to 10 optimizations per day from the same IP. Beyond that, wait 24h or create an account.
Which AI models can use the optimized prompt?
The optimizer works with every assistant, from ChatGPT to Llama. By default it applies principles that hold everywhere: describe the expected result, give the useful context. The "Target model" menu is optional. If you pick ChatGPT, Claude or Gemini, the optimizer adds up to six guidelines taken from the vendor's official guides, for example on how to ask for a specific answer format. Each brand has its own page in the Learn section, with the current models and the date of the last check.
How many iterations to get a good prompt?
Generally, 1 to 2 iterations are enough to transform a vague prompt into an expert one. Beyond 3 iterations, it's better to manually adjust the details rather than letting the AI keep rephrasing.
Why optimize a prompt rather than writing it directly?
Writing a good prompt from scratch requires experience and time (5-10 minutes). Optimizing via AI takes 5 seconds and fixes what people often forget when writing by hand, such as the expected result or the output format.