ChatGPT-4o (March 2025) vs Gemini 2.5 Flash Preview 05-20 (thinking)
Compare ChatGPT-4o (March 2025) by OpenAI against Gemini 2.5 Flash Preview 05-20 (thinking) by Google AI, context windows of 128K vs 1.0M, tested across 7 shared challenges. Updated April 2026.
Which is better, ChatGPT-4o (March 2025) or Gemini 2.5 Flash Preview 05-20 (thinking)?
ChatGPT-4o (March 2025) and Gemini 2.5 Flash Preview 05-20 (thinking) are both competitive models. ChatGPT-4o (March 2025) costs $5/M input tokens vs $0.15/M for Gemini 2.5 Flash Preview 05-20 (thinking). Context windows: 128K vs 1049K tokens. Compare their real outputs side by side below.
Key Differences Between ChatGPT-4o (March 2025) and Gemini 2.5 Flash Preview 05-20 (thinking)
ChatGPT-4o (March 2025) is made by openai while Gemini 2.5 Flash Preview 05-20 (thinking) is from google. ChatGPT-4o (March 2025) has a 128K token context window compared to Gemini 2.5 Flash Preview 05-20 (thinking)'s 1049K. On pricing, ChatGPT-4o (March 2025) costs $5/M input tokens vs $0.15/M for Gemini 2.5 Flash Preview 05-20 (thinking).
No community votes yet. On paper, these are closely matched - try both with your actual task to see which fits your workflow.
Gemini 2.5 Flash Preview 05-20 (thinking) is 4.3x cheaper per token — worth considering if cost matters.
Style Comparison
ChatGPT-4o (March 2025) uses 51.6x more hedging
vsAsk them anything yourself
Some models write identically. You are paying for the brand.
178 models fingerprinted across 32 writing dimensions. Free research.
185x
price gap between models that write identically
178
models
12
clone pairs
32
dimensions
279 AI models invented the same fake scientist.
We read every word. 250 models. 2.14 million words. This is what we found.
