Best AI for essay writing / head-to-head

Gemini 3.1 Pro Preview vs Grok 4.5for essay writing

The verdict

Dead heat: 83 each

Same 12 essay writing tasks, marked blind by three rival labs. Tested 13 Aug 2026.

Where they differed most

The task — Fix the structure

This paragraph makes three points at once and repeats itself. Rewrite it as three short paragraphs, one point each, no repetition: 'Exercise is good for your body and it also helps your mood, and being active reduces the risk of heart disease, plus people who exercise often sleep better, and of course it is good for the heart.'

Exercise provides a natural boost to your mental well-being. Staying active is a great way to elevate your overall mood. 

Regular physical activity is also essential for your cardiovascular health. It strengthens your body and significantly reduces your risk of developing heart disease.

Finally, working out improves the quality of your rest. People who maintain a consistent exercise routine tend to sleep much better at night.
Exercise strengthens your body and lowers the risk of heart disease.

It also improves your mood.

People who exercise regularly tend to sleep better.

Task by task

TaskGemini 3.1 Pro PreviewGrok 4.5
Structured argument85
Essay plan108
Tighten flabby prose99
Hold a word count108
Adapt for the reader1010
Introduction only910
Steelman the other side89
Cite honestly45
Fix the structure510
Formal to plain910
Conclusion that adds something98
Refuse to pad98

Full receipts: Gemini 3.1 Pro Preview, Grok 4.5 · judges claude-sonnet-5, gpt-5.6-terra, grok-4.5

Questions people ask

Which is better for essay writing: Gemini 3.1 Pro Preview or Grok 4.5?

They tied at 83/100 on our essay writing suite — for this job, pick on price or the product you already use.

How was this tested?

Both models answered the identical published essay writing tasks. Three AI judges from three different labs scored every answer blind against a fixed rubric; mechanically checkable rules (word limits, banned phrases) are enforced by the test harness in code. The raw outputs and judge verdicts are downloadable.

More essay writing head-to-heads: Gemini 3.1 Pro Preview vs GPT-5.6 Sol · GPT-5.6 Sol vs Grok 4.5 · Gemini 3.1 Pro Preview vs GPT-5.5 · GPT-5.5 vs Grok 4.5 · Gemini 3.1 Pro Preview vs GPT-5.6 Luna · GPT-5.6 Luna vs Grok 4.5

Full ranking: Best AI for essay writing · model pages: Gemini 3.1 Pro Preview, Grok 4.5