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Claude Sonnet 5.5 vs Llama 3.1 405B Instruct

Claude Sonnet 5.5 leads the LLM Stats Score 58.1 to 14.7. Llama 3.1 405B Instruct is 4.5x cheaper per token.

Anthropic · Meta · Updated for 2026

Which is better?

Claude Sonnet 5.5 leads the overall LLM Stats Score 58.1 to 14.7, ranking #3 overall.

On price, Llama 3.1 405B Instruct is roughly 4.5x cheaper per token on a blended 3:1 input/output basis, which adds up quickly at production volume.

Claude Sonnet 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 Sonnet 5.5

  • overall performance matters — it scores 58.1 and ranks #3 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 Llama 3.1 405B Instruct

  • cost matters — it's about 4.5x cheaper per token
  • you need open weights you can self-host or fine-tune

At a glance

The differences that matter most.

Claude Sonnet 5.5
Anthropic
Llama 3.1 405B Instruct
Meta
Core performance indexes
LLM Stats Score
58.1
#3
14.7
#240
Reasoning
56.6
#3
13.8
#240
Coding
48.9
#2
11.5
#161
Cost, coverage & limits
Benchmark wins
—
—
Input price
$2.00 / M
$0.89 / M
Output price
$10.00 / M
$0.89 / M
Context window
1,000,000
128,000

Capability indexes

Additional strengths measured across groups of related public benchmarks

2 shared
Index
Claude Sonnet 5.5
Llama 3.1 405B Instruct
Math
36.9#34
19.3#170
Tool use
33.9#2
30.8#5
Conservative TrueSkill rating · higher is betterHow scores work

Individual benchmarks

47 reported for Claude Sonnet 5.5 · 18 for Llama 3.1 405B Instruct

No common benchmarks found

Claude Sonnet 5.5 and Llama 3.1 405B Instructdon'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

Llama 3.1 405B Instruct costs less

For input processing, Claude Sonnet 5.5 ($2.00/1M tokens) is 2.2x more expensive than Llama 3.1 405B Instruct ($0.89/1M tokens).

For output processing, Claude Sonnet 5.5 ($10.00/1M tokens) is 11.2x more expensive than Llama 3.1 405B Instruct ($0.89/1M tokens).

In conclusion, Claude Sonnet 5.5 is more expensive than Llama 3.1 405B Instruct.*

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

Lowest available price from all providers
Tue Sep 29 2026 • llm-stats.com
Anthropic
Claude Sonnet 5.5
Input tokens$2.00
Output tokens$10.00
Best providerAnthropic
Meta
Llama 3.1 405B Instruct
Input tokens$0.89
Output tokens$0.89
Best providerLambda
Notice missing or incorrect data?Start an Issue→

Context Window

Maximum input and output token capacity

Claude Sonnet 5.5 accepts 1,000,000 input tokens compared to Llama 3.1 405B Instruct's 128,000 tokens. Both models can generate responses up to 128,000 tokens.

Anthropic
Claude Sonnet 5.5
Input1,000,000 tokens
Output128,000 tokens
Meta
Llama 3.1 405B Instruct
Input128,000 tokens
Output128,000 tokens
Tue Sep 29 2026 • llm-stats.com

Input capabilities

Documented input modalities across available providers

Claude Sonnet 5.5 supports multimodal inputs, whereas Llama 3.1 405B Instruct does not.

Claude Sonnet 5.5 can handle both text and other forms of data like images, making it suitable for multimodal applications.

Claude Sonnet 5.5

Text
Images
Audio
Video

Llama 3.1 405B Instruct

Text
Images
Audio
Video

License

Usage and distribution terms

Claude Sonnet 5.5 is licensed under a proprietary license, while Llama 3.1 405B Instruct uses Llama 3.1 Community License.

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

Claude Sonnet 5.5

Proprietary

Closed source

Llama 3.1 405B Instruct

Llama 3.1 Community License

Open weights

Release Timeline

When each model was launched

Claude Sonnet 5.5 was released on 2026-09-28, while Llama 3.1 405B Instruct was released on 2024-07-23.

Claude Sonnet 5.5 is 27 months newer than Llama 3.1 405B Instruct.

Claude Sonnet 5.5

Sep 28, 2026

1 days ago

2.2yr newer
Llama 3.1 405B Instruct

Jul 23, 2024

2.2 years ago

Knowledge Cutoff

When training data ends

Claude Sonnet 5.5 has a documented knowledge cutoff of 2026-06-01, while Llama 3.1 405B Instruct's cutoff date is not specified.

We can confirm Claude Sonnet 5.5's training data extends to 2026-06-01, but cannot make a direct comparison without Llama 3.1 405B Instruct's cutoff date.

Claude Sonnet 5.5

Jun 2026

Llama 3.1 405B Instruct

—

Provider Availability

Claude Sonnet 5.5 is available from Anthropic. Llama 3.1 405B Instruct is available from Lambda, DeepInfra, Fireworks, Bedrock, Together, Hyperbolic, Google, Replicate.

Claude Sonnet 5.5

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

Llama 3.1 405B Instruct

lambda logo
Lambda
Input Price:Input: $0.89/1MOutput Price:Output: $0.89/1M
deepinfra logo
Deepinfra
Input Price:Input: $1.79/1MOutput Price:Output: $1.79/1M
fireworks logo
Fireworks
Input Price:Input: $3.00/1MOutput Price:Output: $3.00/1M
bedrock logo
AWS Bedrock
Input Price:Input: $3.00/1MOutput Price:Output: $3.00/1M
together logo
Together
Input Price:Input: $3.50/1MOutput Price:Output: $3.50/1M
hyperbolic logo
Hyperbolic
Input Price:Input: $4.00/1MOutput Price:Output: $4.00/1M
google logo
Google
Input Price:Input: $5.00/1MOutput Price:Output: $16.00/1M
replicate logo
Replicate
Input Price:Input: $9.50/1MOutput Price:Output: $9.50/1M
* Prices shown are per million tokens

Outputs Comparison

Notice missing or incorrect data?Start an Issue discussion→

Judge for yourself.

Run your own prompts against Claude Sonnet 5.5 and Llama 3.1 405B Instruct side-by-side, then vote on the output you prefer.

Claude Sonnet 5.5
✓ Preferred
Llama 3.1 405B Instruct
Open in Playground

FAQ

Common questions about Claude Sonnet 5.5 vs Llama 3.1 405B Instruct.

Which is better, Claude Sonnet 5.5 or Llama 3.1 405B Instruct?

Claude Sonnet 5.5 leads the LLM Stats Score 58.1 to 14.7. Claude Sonnet 5.5 is made by Anthropic and Llama 3.1 405B Instruct is made by Meta. 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 Llama 3.1 405B Instruct 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%. Llama 3.1 405B Instruct scores ARC-C: 96.9%, GSM8k: 96.8%, API-Bank: 92.0%, Multilingual MGSM (CoT): 91.6%, HumanEval: 89.0%.

Is Claude Sonnet 5.5 cheaper than Llama 3.1 405B Instruct?

Llama 3.1 405B Instruct is 2.2x cheaper for input tokens. Claude Sonnet 5.5 costs $2.00/M input and $10.00/M output via anthropic. Llama 3.1 405B Instruct costs $0.89/M input and $0.89/M output via lambda.

What are the context window sizes for Claude Sonnet 5.5 and Llama 3.1 405B Instruct?

Claude Sonnet 5.5 supports 1.0M tokens and Llama 3.1 405B Instruct supports 128K 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 Llama 3.1 405B Instruct?

Key differences include LLM Stats Score (58.1 vs 14.7), context window (1.0M vs 128K), input pricing ($2.00 vs $0.89/M), multimodal support (yes vs no), licensing (Proprietary vs Llama 3.1 Community License). See the full comparison above for benchmark-by-benchmark results.

Who makes Claude Sonnet 5.5 and Llama 3.1 405B Instruct?

Claude Sonnet 5.5 is developed by Anthropic and Llama 3.1 405B Instruct is developed by Meta.

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