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Claude Opus 5.5 vs Gemini 2.0 Flash Thinking

Claude Opus 5.5 leads the LLM Stats Score 59.7 to 16.7.

Anthropic · Google · Updated for 2026

Which is better?

Claude Opus 5.5 leads the overall LLM Stats Score 59.7 to 16.7, ranking #1 overall.

Based on current LLM Stats indexes, shared benchmarks, pricing, and model metadata for 2026.

Choose Claude Opus 5.5

  • overall performance matters — it scores 59.7 and ranks #1 on LLM Stats
  • your work emphasizes reasoning — it leads those capability indexes
  • you want the most recent training data — it shipped Sep 2026

Choose Gemini 2.0 Flash Thinking

  • you are already invested in the Google ecosystem

At a glance

The differences that matter most.

Claude Opus 5.5
Anthropic
Gemini 2.0 Flash Thinking
Google
Core performance indexes
LLM Stats Score
59.7
#1
16.7
#225
Reasoning
57.8
#1
17.0
#218
Cost, coverage & limits
Benchmark wins
—
—
Input price
$4.00 / M
— / M
Output price
$20.00 / M
— / M
Context window
1,000,000
—

Individual benchmarks

31 reported for Claude Opus 5.5 · 3 for Gemini 2.0 Flash Thinking

No common benchmarks found

Claude Opus 5.5 and Gemini 2.0 Flash Thinkingdon't have any common benchmark datasets to compare. They may have been evaluated on different testing suites.

Human preference

Blind head-to-head votes and playground preference scores

Context Window

Maximum input and output token capacity

Only Claude Opus 5.5 specifies input context (1,000,000 tokens). Only Claude Opus 5.5 specifies output context (128,000 tokens).

Anthropic
Claude Opus 5.5
Input1,000,000 tokens
Output128,000 tokens
Google
Gemini 2.0 Flash Thinking
Input- tokens
Output- tokens
Wed Sep 23 2026 • llm-stats.com

Input capabilities

Documented input modalities across available providers

Both Claude Opus 5.5 and Gemini 2.0 Flash Thinking support multimodal inputs.

They are both capable of processing various types of data, offering versatility in application.

Claude Opus 5.5

Text
Images
Audio
Video

Gemini 2.0 Flash Thinking

Text
Images
Audio
Video

License

Usage and distribution terms

Both models are licensed under proprietary licenses.

Both models have usage restrictions defined by their respective organizations.

Claude Opus 5.5

Proprietary

Closed source

Gemini 2.0 Flash Thinking

Proprietary

Closed source

Release Timeline

When each model was launched

Claude Opus 5.5 was released on 2026-09-22, while Gemini 2.0 Flash Thinking was released on 2025-01-21.

Claude Opus 5.5 is 20 months newer than Gemini 2.0 Flash Thinking.

Claude Opus 5.5

Sep 22, 2026

0 days ago

1.7yr newer
Gemini 2.0 Flash Thinking

Jan 21, 2025

1.7 years ago

Knowledge Cutoff

When training data ends

Claude Opus 5.5 has a knowledge cutoff of 2026-06-01, while Gemini 2.0 Flash Thinking has a cutoff of 2024-08-01.

Claude Opus 5.5 has more recent training data (up to 2026-06-01), making it potentially better informed about events through that date compared to Gemini 2.0 Flash Thinking (2024-08-01).

Claude Opus 5.5

Jun 2026

1.8 yr newer
Gemini 2.0 Flash Thinking

Aug 2024

Outputs Comparison

Notice missing or incorrect data?Start an Issue discussion→

Judge for yourself.

Run your own prompts against Claude Opus 5.5 and Gemini 2.0 Flash Thinking side-by-side, then vote on the output you prefer.

Claude Opus 5.5
✓ Preferred
Gemini 2.0 Flash Thinking
Open in Playground

FAQ

Common questions about Claude Opus 5.5 vs Gemini 2.0 Flash Thinking.

Which is better, Claude Opus 5.5 or Gemini 2.0 Flash Thinking?

Claude Opus 5.5 leads the LLM Stats Score 59.7 to 16.7. Claude Opus 5.5 is made by Anthropic and Gemini 2.0 Flash Thinking is made by Google. The best choice depends on your use case — compare their capability indexes, individual benchmarks, pricing, and limits above.

How does Claude Opus 5.5 compare to Gemini 2.0 Flash Thinking in benchmarks?

Claude Opus 5.5 scores BenchCAD (with Python tool): 96.2%, Global-MMLU: 94.3%, SWE-bench Multilingual: 93.9%, MILU: 93.1%, ArXivMath: 91.2%. Gemini 2.0 Flash Thinking scores MMMU: 75.4%, GPQA: 74.2%, AIME 2024: 73.3%.

What are the context window sizes for Claude Opus 5.5 and Gemini 2.0 Flash Thinking?

Claude Opus 5.5 supports 1.0M tokens and Gemini 2.0 Flash Thinking supports an unknown number of tokens. A larger context window lets you process longer documents, conversations, or codebases in a single request.

What are the main differences between Claude Opus 5.5 and Gemini 2.0 Flash Thinking?

Key differences include LLM Stats Score (59.7 vs 16.7). See the full comparison above for benchmark-by-benchmark results.

Who makes Claude Opus 5.5 and Gemini 2.0 Flash Thinking?

Claude Opus 5.5 is developed by Anthropic and Gemini 2.0 Flash Thinking is developed by Google.

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