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AnthropicClaude Opus 4.8VSGoogleGemini 3.5 Flash

Analysis by:the whichllmmodel Editorial Team|Updated: June 2026

Our Take

We recommend Claude Opus 4.8 if your workflow requires peak coding capability, or the 3.0x cheaper Gemini 3.5 Flash to optimize your API budget. While both models deliver similar reasoning performance, Claude Opus 4.8 holds a clear lead in coding. Choose Claude Opus 4.8 for complex development tasks, or Gemini 3.5 Flash for cost optimization.
▶WHY?
Benchmark Calculations & Evidence:
  • Coding Benchmarks: Both models were evaluated on the SWE-bench Pro benchmark. Claude Opus 4.8 scored 69.2%, while Gemini 3.5 Flash scored 55.1%.
  • Reasoning Benchmarks: Both models were evaluated on the GPQA Diamond benchmark. Claude Opus 4.8 scored 93.6%, while Gemini 3.5 Flash scored 92.2%.
  • Cost Efficiency: Gemini 3.5 Flash pricing ($1.5/M input, $9/M output) is 3.0x cheaper than Claude Opus 4.8 ($5/M input, $25/M output).
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    Model Specs

    Claude Opus 4.8

    Website

    Benchmarks & Scores

    Coding (swe-bench-pro)Winner (+14.1%)
    69.2%

    complex codebases, multi-file repositories, and architectural planning

    Reasoning (gpqa-diamond)Winner (+1.4%)
    93.6%

    graduate-level science QA

    Cost & Context

    Cost (per 1M tokens)
    $10.00Input: $5.00 | Output: $25.00
    Context Window
    1.05M tokens
    Model Specs

    Gemini 3.5 Flash

    Website

    Benchmarks & Scores

    Coding (swe-bench-pro)
    55.1%

    complex codebases, multi-file repositories, and architectural planning

    Reasoning (gpqa-diamond)
    92.2%

    graduate-level science QA

    Cost & Context

    Cost (per 1M tokens)3.0x cheaper
    $3.38Input: $1.50 | Output: $9.00
    Context Window
    1.05M tokens
    Read our data collection methodology

    Frequently Asked Questions about Claude Opus 4.8 vs Gemini 3.5 Flash

    Gemini 3.5 Flash is cheaper than Claude Opus 4.8. Gemini 3.5 Flash has a blended cost of $3.38/1M tokens, which is about 3.0x cheaper than Claude Opus 4.8 at $10.00/1M tokens.

    Claude Opus 4.8 is better for coding tasks on this benchmark. It scores 69.2% on swe-bench-pro (complex codebases, multi-file repositories, and architectural planning) compared to Gemini 3.5 Flash which scores 55.1%.

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