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Claude Opus 5.5 vs Mistral Small 4

Claude Opus 5.5 leads the LLM Stats Score 60.3 to 19.0. Mistral Small 4 is 30.5x cheaper per token.

Anthropic · Mistral AI · Updated for 2026

Which is better?

Claude Opus 5.5 leads the overall LLM Stats Score 60.3 to 19.0, ranking #1 overall.

On price, Mistral Small 4 is roughly 30.5x cheaper per token on a blended 3:1 input/output basis, which adds up quickly at production volume.

Claude Opus 5.5 also accepts a larger context window (1,000,000 input tokens), making it the stronger choice for long documents and large codebases.

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

Choose Claude Opus 5.5

  • overall performance matters — it scores 60.3 and ranks #1 on LLM Stats
  • your work emphasizes reasoning and coding — it leads those capability indexes
  • you process long inputs — it offers a 1,000,000 token context window
  • you want the most recent training data — it shipped Sep 2026

Choose Mistral Small 4

  • cost matters — it's about 30.5x cheaper per token
  • you need open weights you can self-host or fine-tune

At a glance

The differences that matter most.

Claude Opus 5.5
Anthropic
Mistral Small 4
Mistral AI
Core performance indexes
LLM Stats Score
60.3
#1
19.0
#217
Reasoning
58.4
#1
19.9
#199
Coding
51.4
#1
10.7
#170
Cost, coverage & limits
Benchmark wins
—
—
Input price
$4.00 / M
$0.15 / M
Output price
$20.00 / M
$0.60 / M
Context window
1,000,000
256,000

Capability indexes

Additional strengths measured across groups of related public benchmarks

1 shared
Index
Claude Opus 5.5
Mistral Small 4
Math
42.7#4
19.0#172
Conservative TrueSkill rating · higher is betterHow scores work

Individual benchmarks

31 reported for Claude Opus 5.5 · 9 for Mistral Small 4

No common benchmarks found

Claude Opus 5.5 and Mistral Small 4don'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

Pricing Analysis

Price comparison per million tokens

Mistral Small 4 costs less

For input processing, Claude Opus 5.5 ($4.00/1M tokens) is 26.7x more expensive than Mistral Small 4 ($0.15/1M tokens).

For output processing, Claude Opus 5.5 ($20.00/1M tokens) is 33.3x more expensive than Mistral Small 4 ($0.60/1M tokens).

In conclusion, Claude Opus 5.5 is more expensive than Mistral Small 4.*

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

Lowest available price from all providers
Tue Oct 06 2026 • llm-stats.com
Anthropic
Claude Opus 5.5
Input tokens$4.00
Output tokens$20.00
Best providerAnthropic
Mistral AI
Mistral Small 4
Input tokens$0.15
Output tokens$0.60
Best providerMistral
Notice missing or incorrect data?

Context Window

Maximum input and output token capacity

Claude Opus 5.5 accepts 1,000,000 input tokens compared to Mistral Small 4's 256,000 tokens. Mistral Small 4 can generate longer responses up to 256,000 tokens, while Claude Opus 5.5 is limited to 128,000 tokens.

Anthropic
Claude Opus 5.5
Input1,000,000 tokens
Output128,000 tokens
Mistral AI
Mistral Small 4
Input256,000 tokens
Output256,000 tokens
Tue Oct 06 2026 • llm-stats.com

Input capabilities

Documented input modalities across available providers

Both Claude Opus 5.5 and Mistral Small 4 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

Mistral Small 4

Text
Images
Audio
Video

License

Usage and distribution terms

Claude Opus 5.5 is licensed under a proprietary license, while Mistral Small 4 uses Apache 2.0.

License differences may affect how you can use these models in commercial or open-source projects.

Claude Opus 5.5

Proprietary

Closed source

Mistral Small 4

Apache 2.0

Open weights

Release Timeline

When each model was launched

Claude Opus 5.5 was released on 2026-09-22, while Mistral Small 4 was released on 2026-03-16.

Claude Opus 5.5 is 6 months newer than Mistral Small 4.

Claude Opus 5.5

Sep 22, 2026

2 weeks ago

6mo newer
Mistral Small 4

Mar 16, 2026

6 months ago

Knowledge Cutoff

When training data ends

Claude Opus 5.5 has a documented knowledge cutoff of 2026-06-01, while Mistral Small 4's cutoff date is not specified.

We can confirm Claude Opus 5.5's training data extends to 2026-06-01, but cannot make a direct comparison without Mistral Small 4's cutoff date.

Claude Opus 5.5

Jun 2026

Mistral Small 4

—

Provider Availability

Claude Opus 5.5 is available from Anthropic. Mistral Small 4 is available from Mistral AI.

Claude Opus 5.5

anthropic logo
Anthropic
Input Price:Input: $4.00/1MOutput Price:Output: $20.00/1M

Mistral Small 4

mistral logo
Mistral
Input Price:Input: $0.15/1MOutput Price:Output: $0.60/1M
* Prices shown are per million tokens

Outputs Comparison

Notice missing or incorrect data?

Judge for yourself.

Run your own prompts against Claude Opus 5.5 and Mistral Small 4 side-by-side, then vote on the output you prefer.

Claude Opus 5.5
✓ Preferred
Mistral Small 4
Open in Playground

FAQ

Common questions about Claude Opus 5.5 vs Mistral Small 4.

Which is better, Claude Opus 5.5 or Mistral Small 4?

Claude Opus 5.5 leads the LLM Stats Score 60.3 to 19.0. Claude Opus 5.5 is made by Anthropic and Mistral Small 4 is made by Mistral AI. 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 Mistral Small 4 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%. Mistral Small 4 scores AIME 2025: 83.8%, MMLU-Pro: 78.0%, AA-LCR: 71.2%, GPQA: 71.2%, LiveCodeBench: 63.6%.

Is Claude Opus 5.5 cheaper than Mistral Small 4?

Mistral Small 4 is 26.7x cheaper for input tokens. Claude Opus 5.5 costs $4.00/M input and $20.00/M output via anthropic. Mistral Small 4 costs $0.15/M input and $0.60/M output via mistral.

What are the context window sizes for Claude Opus 5.5 and Mistral Small 4?

Claude Opus 5.5 supports 1.0M tokens and Mistral Small 4 supports 256K 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 Mistral Small 4?

Key differences include LLM Stats Score (60.3 vs 19.0), context window (1.0M vs 256K), input pricing ($4.00 vs $0.15/M), licensing (Proprietary vs Apache 2.0). See the full comparison above for benchmark-by-benchmark results.

Who makes Claude Opus 5.5 and Mistral Small 4?

Claude Opus 5.5 is developed by Anthropic and Mistral Small 4 is developed by Mistral AI.

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