o3 Mini vs Gemini 2.5 Flash Preview

Compare o3 Mini by OpenAI against Gemini 2.5 Flash Preview by Google AI, context windows of 64K vs 1.0M, tested across 21 shared challenges. Updated March 2026.

Which is better, o3 Mini or Gemini 2.5 Flash Preview?

o3 Mini and Gemini 2.5 Flash Preview are both competitive models. o3 Mini costs $1.1/M input tokens vs $0.15/M for Gemini 2.5 Flash Preview. Context windows: 64K vs 1049K tokens. Compare their real outputs side by side below.

Key Differences Between o3 Mini and Gemini 2.5 Flash Preview

o3 Mini is made by openai while Gemini 2.5 Flash Preview is from google. o3 Mini has a 64K token context window compared to Gemini 2.5 Flash Preview's 1049K. On pricing, o3 Mini costs $1.1/M input tokens vs $0.15/M for Gemini 2.5 Flash Preview.

Our Verdict
Gemini 2.5 Flash Preview
Gemini 2.5 Flash Preview
o3 Mini
o3 MiniRunner-up

No community votes yet. On paper, Gemini 2.5 Flash Preview has the edge — bigger model tier, newer, bigger context window.

Gemini 2.5 Flash Preview is 7.3x cheaper per token — worth considering if cost matters.

Slight edge
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