Why using AI to train ENEM essay writing makes sense in 2026

ENEM requires a dissertation-argumentative essay that intimidates many: you have up to 30 lines to defend a thesis with solid arguments, intervention proposal and mastery of formal language. Training this skill requires constant feedback, and that’s exactly where artificial intelligence tools become real allies. The good news is that several quality AIs are available for free, or with generous free plans, and work well in Portuguese.

This comparison brings together the main accessible options in Brazil for those preparing for ENEM 2026. The selection criterion is not which AI is “smarter” in general, but which delivers useful correction, consistent with the grading board’s criteria (INEP evaluates five competencies, from language mastery to intervention proposal), and charges nothing or almost nothing. Whether you study on your own, take a prep course, or simply want a reviewer available at 2 AM, keep reading.

Comparison table: Free AIs for ENEM essay writing

Prices vary according to each company’s policy. Confirm availability and limits directly on each tool’s website before using.

ChatGPT: the most versatile, but requires the right prompt

ChatGPT, developed by OpenAI, is probably the AI you already know by name. In the free plan in 2026, the main access is via GPT-4o mini, a lighter model, with limited windows of use of the full GPT-4o throughout the day. For ENEM essay writing, this is sufficient in most cases.

The central point here is that ChatGPT is not born “programmed” to correct ENEM essays. You need to teach it what you want. A good correction prompt would be something like: “Correct this essay based on the five ENEM competencies. Evaluate each with a score of 0 to 200 and justify.” With this direction, feedback quality improves significantly. Without specific instruction, you receive a generic critique that doesn’t differentiate competency I (language mastery) from competency V (intervention proposal).

For whom it’s useful: students who already have a basic understanding of ENEM competencies and want a flexible reviewer, also capable of explaining concepts, suggesting cultural references, and simulating essay topics. Not suitable for those who want automatic feedback without having to formulate the request, nor for those with unstable connections, since the service depends on good internet.

Gemini: Google integration and good Portuguese performance

Gemini, from Google, has a clear competitive advantage for Brazilian students: integration with the Google ecosystem. If you use Gmail, Docs, or Drive, you already have easy access. In the free plan, Gemini 1.5 Flash is the standard model, according to Google itself, and handles long texts well, which is useful for sending the complete essay and asking for detailed analysis.

In Portuguese, Gemini performs solidly. It understands language nuances, identifies cohesion deviations (logical connection between text parts) and coherence issues (consistency of ideas) with reasonable accuracy. Like ChatGPT, you’ll do better asking explicitly for analysis by ENEM competency. Gemini tends to be more detailed in grammatical explanations when requested, which is an advantage for those who want to understand the error, not just correct it.

One caution: the free model has daily usage limits that may vary. Google doesn’t publish fixed numbers publicly, so keep an eye out if you’re using it in long study sessions.

Microsoft Copilot: GPT-4o access without paid subscription

Microsoft Copilot is one of the most underrated options on this list. It runs with GPT-4o technology (according to Microsoft) in the free plan, without needing a subscription, just a Microsoft account. For those using Windows or who already have an Outlook account, it’s the most direct way to access a powerful model without paying.

In practice, for ENEM essay writing, Copilot works very similarly to ChatGPT, since the engine is similar. The difference is in the interface and some context limitations (the amount of information the AI can process at once). For a 30-line essay followed by a request for detailed correction, it handles it without problems.

Practical tip: Copilot has “creative,” “balanced,” and “precise” modes. For essay correction, balanced mode usually generates more useful responses, because it’s neither as generic as creative nor as dry as precise.

Claude: the most careful with Portuguese text

Claude, from Anthropic, is known for a more careful and extensive response style. The free plan gives access to Claude 3.5 Haiku, according to Anthropic, which is already quite capable for textual analysis. For essays, this translates to more elaborate feedback on style, fluidity, and argumentation.

Claude tends to point out not just what’s wrong, but also why it’s wrong and how to rewrite it. This level of detail is especially useful for students who want to understand the logic behind the correction, not just receive a score. The limitation of the free plan is the number of messages per period, which Anthropic doesn’t publicly detail with precision, so it’s recommended to check directly on the platform.

In Brazil, Claude is accessed via web (claude.ai) without a consolidated native app for Android or iOS with the same functionality level, which can be a drawback for those who study on mobile.

Native ENEM essay correction platforms: less flexible, more direct

There are Brazilian platforms developed specifically for ENEM essay correction, such as Essay Online, Descomplica, and Stoodi, among others. They use AI (generally proprietary or integrated models) and already deliver the competency score without you needing to formulate any prompt.

The advantage is objectivity: you submit the essay, receive the structured diagnosis, sometimes with paragraph-by-paragraph comments. The disadvantage is that feedback is usually less rich than a well-instructed general language model, and many charge for additional corrections beyond the basic free plan. Check the current conditions of each platform, as plans change frequently.

For those in the final preparation phase who want to simulate the grading board’s experience quickly, these platforms have value. For those who want to learn while correcting, general-purpose AIs are more useful.

How to use any AI to correct your ENEM essay: step by step

1. Write your complete essay on paper or in a text editor, without AI help.
2. Open the chosen tool and paste this prompt before the text: “You are an ENEM essay corrector. Correct the text below evaluating the five ENEM competencies (language mastery, theme comprehension, argument selection, cohesion and coherence, intervention proposal). Give a score of 0 to 200 for each competency and explain the points to improve.”
3. Paste your essay right below the prompt and send.
4. Read the competency-by-competency feedback and note the critical points.
5. Rewrite the essay based on the suggestions and repeat the process.

This rewriting cycle is what really develops the skill. The AI serves as a mirror, not a substitute for effort.

Which AI to choose based on your profile

If you want maximum flexibility and already understand ENEM competencies, ChatGPT or Claude are the best choices. Both respond well to specific prompts and deliver rich analysis.

If you heavily use the Google ecosystem and want convenience without friction, Gemini is the natural path. Integration with Google Docs, for example, makes it easier to work on the essay and request feedback without leaving the environment.

If you don’t want to pay anything and want access to a robust model, Microsoft Copilot is the option that delivers the most power for free, without requiring a premium account.

If you want quick and structured feedback without thinking about the prompt, a native ENEM essay correction platform like Essay Online can be more efficient, even if feedback is less deep.

An important note: none of these tools replace reading reference texts, studying INEP criteria, and the habit of writing frequently. AI speeds up the feedback cycle, but learning depends on your interpretation of the corrections and consistent practice. If you also use technology for other study purposes and wonder how much hardware matters in this equation, it’s worth noting that discussions about local AI performance, such as analyzing whether RTX 5070 is worth it in 2026, show how the AI sector is increasingly integrated into everyday life, including education.

Frequently asked questions about AI for ENEM essay writing

Can AI give a score equal to INEP’s?

Not with that guarantee. AIs are estimation and textual analysis tools, they don’t replicate INEP’s human process. The generated score serves as a training reference, not as a prediction of the actual result. Use it as a thermometer, not as absolute truth.

Is it dishonest to use AI to improve my training essay?

No. Using AI in training is equivalent to using an annotated answer sheet or having a teacher review your text. What matters is that on exam day you write alone. The goal of training is to develop skill, and AI is a tool for that.

Which tool works best on mobile?

ChatGPT has a native app for Android and iOS with good experience. Gemini also has integrated Google app. Claude has mobile access via browser, but the app still doesn’t offer full parity with the web version. Copilot has an app available in app stores.

Do I need fast internet to use these AIs?

Yes, all listed tools are cloud-based and depend on stable connection. There’s no relevant offline version for educational use of these tools at the free level. If your connection is unstable, prefer to make queries in bulk, not line by line.

Choose the tool, build your routine, and start today

The best comparison doesn’t solve anything if you don’t sit down to write. Choose one tool from this guide, save the competency-based correction prompt, and set a simple goal: one essay per week, with rewriting after feedback. This pace, maintained for a few months until ENEM 2026, will make more difference than any premium resource. AI is the reviewer available anytime; the work is, inevitably, yours.