GoogleGemini 2.5 FlashVSOpenAIGPT-5.5
Our Take
We recommend GPT-5.5 if you need peak intelligence for complex complex codebases, multi-file repositories, and architectural planning, or the 13.2x cheaper Gemini 2.5 Flash if your workflow is limited to multi-file code and clearly defined tasks. While GPT-5.5 holds a major reasoning advantage, Gemini 2.5 Flash is optimized for high-volume budget pipelines. Choose GPT-5.5 for architectural codebase planning, or Gemini 2.5 Flash to maximize your budget for basic scripts.
▶WHY?
Benchmark Calculations & Evidence:
Coding Evaluation: Gemini 2.5 Flash was evaluated on SWE-bench Verified (scoring 60.4%), while GPT-5.5 was evaluated on SWE-bench Pro (scoring 58.6%).
Reasoning Accuracy: Both models were evaluated on the GPQA Diamond benchmark. GPT-5.5 scored 93.6%, while Gemini 2.5 Flash scored 68.3%.
Cost Efficiency: Gemini 2.5 Flash pricing ($0.3/M input, $2.5/M output) is 13.2x cheaper than GPT-5.5 ($5/M input, $30/M output).
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Benchmarks & Scores
Coding (swe-bench-verified)
60.4%multi-file code and clearly defined tasks
Reasoning (gpqa-diamond)
68.3%graduate-level science QA
Cost & Context
Cost (per 1M tokens)13.2x cheaper
$0.85Input: $0.30 | Output: $2.50Context Window
1.05M tokensBenchmarks & Scores
Coding (swe-bench-pro)
58.6%complex codebases, multi-file repositories, and architectural planning
Reasoning (gpqa-diamond)Winner (+25.3%)
93.6%graduate-level science QA
Cost & Context
Cost (per 1M tokens)
$11.25Input: $5.00 | Output: $30.00Context WindowLarger
1.05M tokensFrequently Asked Questions about Gemini 2.5 Flash vs GPT-5.5
Gemini 2.5 Flash is cheaper than GPT-5.5. Gemini 2.5 Flash has a blended cost of $0.85/1M tokens, which is about 13.2x cheaper than GPT-5.5 at $11.25/1M tokens.
For coding tasks, Gemini 2.5 Flash scores 60.4% on swe-bench-verified (multi-file code and clearly defined tasks), while GPT-5.5 scores 58.6% on swe-bench-pro (complex codebases, multi-file repositories, and architectural planning).
Related Matchups
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