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Claude Sonnet 5.5 vs Gemini 3.1 Pro

Claude Sonnet 5.5 leads the LLM Stats Score 58.0 to 43.2. Claude Sonnet 5.5 is 1.1x cheaper per token.

Anthropic · Google · Updated for 2026

Which is better?

Claude Sonnet 5.5 leads the overall LLM Stats Score 58.0 to 43.2, ranking #3 overall.

In the 3 individual benchmarks reported for both models, Claude Sonnet 5.5 wins 3; this is a narrower head-to-head signal than the composite indexes.

On price, Claude Sonnet 5.5 is roughly 1.1x cheaper per token on a blended 3:1 input/output basis, which adds up quickly at production volume.

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

Choose Claude Sonnet 5.5

  • overall performance matters — it scores 58.0 and ranks #3 on LLM Stats
  • your work emphasizes reasoning and coding — it leads those capability indexes
  • you value its reported benchmark strengths — it wins 3 of 3 exact shared results
  • cost matters — it's about 1.1x cheaper per token
  • you want the most recent training data — it shipped Sep 2026

Choose Gemini 3.1 Pro

  • you want predictable pricing at $2.00/M input and $12.00/M output

At a glance

The differences that matter most.

Claude Sonnet 5.5
Anthropic
Gemini 3.1 Pro
Google
Core performance indexes
LLM Stats Score
58.0
#3
43.2
#47
Reasoning
56.6
#3
44.9
#34
Coding
48.8
#2
30.7
#50
Agents
42.3
#3
24.1
#58
Cost, coverage & limits
Benchmark wins
3 of 3
0 of 3
Input price
$2.00 / M
$2.00 / M
Output price
$10.00 / M
$12.00 / M
Context window
1,000,000
1,000,000

Capability indexes

Additional strengths measured across groups of related public benchmarks

3 shared
Index
Claude Sonnet 5.5
Gemini 3.1 Pro
Math
36.9#34
42.4#6
Vision
40.0#3
31.0#30
Tool use
34.0#2
22.8#42
Conservative TrueSkill rating · higher is betterHow scores work

Individual benchmarks

47 reported for Claude Sonnet 5.5 · 20 for Gemini 3.1 Pro

3 shared

Claude Sonnet 5.5 outperforms in 3 benchmarks (DeepSWE 1.1, Legal Agent Benchmark, SWE-Bench Pro), while Gemini 3.1 Pro is better at 0 benchmarks.

Claude Sonnet 5.5 significantly outperforms across most benchmarks.

Fri Oct 02 2026 • llm-stats.com

Human preference

Blind head-to-head votes and playground preference scores

Pricing Analysis

Price comparison per million tokens

Claude Sonnet 5.5 costs less

For input processing, Claude Sonnet 5.5 ($2.00/1M tokens) costs the same as Gemini 3.1 Pro ($2.00/1M tokens).

For output processing, Claude Sonnet 5.5 ($10.00/1M tokens) is 1.2x cheaper than Gemini 3.1 Pro ($12.00/1M tokens).

In conclusion, Gemini 3.1 Pro is more expensive than Claude Sonnet 5.5.*

* Using a 3:1 ratio of input to output tokens

Lowest available price from all providers
Fri Oct 02 2026 • llm-stats.com
Anthropic
Claude Sonnet 5.5
Input tokens$2.00
Output tokens$10.00
Best providerAnthropic
Google
Gemini 3.1 Pro
Input tokens$2.00
Output tokens$12.00
Best providerDeepinfra
Notice missing or incorrect data?

Context Window

Maximum input and output token capacity

Both models have the same input context window of 1,000,000 tokens. Gemini 3.1 Pro can generate longer responses up to 1,000,000 tokens, while Claude Sonnet 5.5 is limited to 128,000 tokens.

Anthropic
Claude Sonnet 5.5
Input1,000,000 tokens
Output128,000 tokens
Google
Gemini 3.1 Pro
Input1,000,000 tokens
Output1,000,000 tokens
Fri Oct 02 2026 • llm-stats.com

Input capabilities

Documented input modalities across available providers

Both Claude Sonnet 5.5 and Gemini 3.1 Pro support multimodal inputs.

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

Claude Sonnet 5.5

Text
Images
Audio
Video

Gemini 3.1 Pro

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 Sonnet 5.5

Proprietary

Closed source

Gemini 3.1 Pro

Proprietary

Closed source

Release Timeline

When each model was launched

Claude Sonnet 5.5 was released on 2026-09-28, while Gemini 3.1 Pro was released on 2026-02-19.

Claude Sonnet 5.5 is 7 months newer than Gemini 3.1 Pro.

Claude Sonnet 5.5

Sep 28, 2026

4 days ago

7mo newer
Gemini 3.1 Pro

Feb 19, 2026

7 months ago

Knowledge Cutoff

When training data ends

Claude Sonnet 5.5 has a knowledge cutoff of 2026-06-01, while Gemini 3.1 Pro has a cutoff of 2025-01-31.

Claude Sonnet 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 3.1 Pro (2025-01-31).

Claude Sonnet 5.5

Jun 2026

1.4 yr newer
Gemini 3.1 Pro

Jan 2025

Provider Availability

Claude Sonnet 5.5 is available from Anthropic. Gemini 3.1 Pro is available from DeepInfra, Google.

Claude Sonnet 5.5

anthropic logo
Anthropic
Input Price:Input: $2.00/1MOutput Price:Output: $10.00/1M

Gemini 3.1 Pro

deepinfra logo
Deepinfra
Input Price:Input: $2.00/1MOutput Price:Output: $12.00/1M
google logo
Google
Input Price:Input: $2.50/1MOutput Price:Output: $15.00/1M
* Prices shown are per million tokens

Outputs Comparison

Notice missing or incorrect data?

Judge for yourself.

Run your own prompts against Claude Sonnet 5.5 and Gemini 3.1 Pro side-by-side, then vote on the output you prefer.

Claude Sonnet 5.5
✓ Preferred
Gemini 3.1 Pro
Open in Playground

FAQ

Common questions about Claude Sonnet 5.5 vs Gemini 3.1 Pro.

Which is better, Claude Sonnet 5.5 or Gemini 3.1 Pro?

Claude Sonnet 5.5 leads the LLM Stats Score 58.0 to 43.2. Claude Sonnet 5.5 is made by Anthropic and Gemini 3.1 Pro 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 Sonnet 5.5 compare to Gemini 3.1 Pro in benchmarks?

Claude Sonnet 5.5 scores BenchCAD (with Python tool): 96.3%, ArXivMath (with tools): 95.2%, Global-MMLU: 92.1%, MILU: 91.6%, SWE-bench Multilingual: 90.3%. Gemini 3.1 Pro scores t2-bench: 99.3%, LiveCodeBench Pro: 96.2%, GPQA: 94.3%, MMMLU: 92.6%, BrowseComp: 85.9%.

Is Claude Sonnet 5.5 cheaper than Gemini 3.1 Pro?

Both models cost $2.00 per million input tokens.

What are the context window sizes for Claude Sonnet 5.5 and Gemini 3.1 Pro?

Claude Sonnet 5.5 supports 1.0M tokens and Gemini 3.1 Pro supports 1.0M tokens. A larger context window lets you process longer documents, conversations, or codebases in a single request.

What are the main differences between Claude Sonnet 5.5 and Gemini 3.1 Pro?

Key differences include LLM Stats Score (58.0 vs 43.2). See the full comparison above for benchmark-by-benchmark results.

Who makes Claude Sonnet 5.5 and Gemini 3.1 Pro?

Claude Sonnet 5.5 is developed by Anthropic and Gemini 3.1 Pro is developed by Google.

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