Gemini 1.5 Pro vs ChatGPT-4o (March 2025)

Compare Gemini 1.5 Pro by Google AI against ChatGPT-4o (March 2025) by OpenAI, context windows of 1.0M vs 128K, tested across 8 shared challenges. Updated April 2026.

Which is better, Gemini 1.5 Pro or ChatGPT-4o (March 2025)?

Gemini 1.5 Pro and ChatGPT-4o (March 2025) are both competitive models. Gemini 1.5 Pro costs $3.5/M input tokens vs $5/M for ChatGPT-4o (March 2025). Context windows: 1000K vs 128K tokens. Compare their real outputs side by side below.

Key Differences Between Gemini 1.5 Pro and ChatGPT-4o (March 2025)

Gemini 1.5 Pro is made by google while ChatGPT-4o (March 2025) is from openai. Gemini 1.5 Pro has a 1000K token context window compared to ChatGPT-4o (March 2025)'s 128K. On pricing, Gemini 1.5 Pro costs $3.5/M input tokens vs $5/M for ChatGPT-4o (March 2025).

Our Verdict
ChatGPT-4o (March 2025)
ChatGPT-4o (March 2025)
Gemini 1.5 Pro
Gemini 1.5 ProRunner-up

No community votes yet. On paper, ChatGPT-4o (March 2025) has the edge — bigger model tier, newer.

Too close to call
Writing DNA

Style Comparison

Similarity
87%

ChatGPT-4o (March 2025) uses 94.5x more emoji

Gemini 1.5 Pro
ChatGPT-4o (March 2025)
61%Vocabulary55%
15wSentence Length24w
0.80Hedging0.52
3.7Bold3.3
3.3Lists6.0
0.00Emoji0.94
0.08Headings0.63
0.09Transitions0.05
Based on 8 + 15 text responses
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Gemini 1.5 ProChatGPT-4o (March 2025)

279 AI models invented the same fake scientist.

We read every word. 250 models. 2.14 million words. This is what we found.

AI Hallucination Index 2026
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