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Claude Sonnet 5.5 vs Muse Spark Open

Claude Sonnet 5.5 leads the LLM Stats Score 58.3 to 44.9. Muse Spark Open is 2.0x cheaper per token.

Anthropic · Meta · Updated for 2026

Which is better?

Claude Sonnet 5.5 leads the overall LLM Stats Score 58.3 to 44.9, ranking #2 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, Muse Spark Open is roughly 2.0x cheaper per token on a blended 3:1 input/output basis, which adds up quickly at production volume.

Muse Spark Open also accepts a larger context window (1,048,576 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 58.3 and ranks #2 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

Choose Muse Spark Open

  • cost matters — it's about 2.0x cheaper per token
  • you process long inputs — it offers a 1,048,576 token context window
  • you want the most recent training data — it shipped Oct 2026
  • you need open weights you can self-host or fine-tune

At a glance

The differences that matter most.

Claude Sonnet 5.5
Anthropic
Muse Spark Open
Meta
Core performance indexes
LLM Stats Score
58.3
#2
44.9
#43
Reasoning
57.1
#3
45.2
#39
Coding
47.5
#2
33.0
#42
Agents
43.2
#3
30.6
#43
Cost, coverage & limits
Benchmark wins
3 of 3
0 of 3
Input price
$2.00 / M
$1.25 / M
Output price
$10.00 / M
$4.25 / M
Context window
1,000,000
1,048,576

Capability indexes

Additional strengths measured across groups of related public benchmarks

4 shared
Index
Claude Sonnet 5.5
Muse Spark Open
Math
38.2#28
31.6#69
Vision
41.4#2
31.2#34
Tool use
35.2#2
23.3#44
Multimodal
41.1#2
33.1#20
Conservative TrueSkill rating · higher is betterHow scores work

Individual benchmarks

47 reported for Claude Sonnet 5.5 · 17 for Muse Spark Open

3 shared

Claude Sonnet 5.5 outperforms in 3 benchmarks (DeepSWE 1.1, Humanity's Last Exam (with tools), Toolathlon-Verified), while Muse Spark Open is better at 0 benchmarks.

Claude Sonnet 5.5 significantly outperforms across most benchmarks.

Mon Oct 19 2026 • llm-stats.com

Human preference

Blind head-to-head votes and playground preference scores

Pricing Analysis

Price comparison per million tokens

Muse Spark Open costs less

For input processing, Claude Sonnet 5.5 ($2.00/1M tokens) is 1.6x more expensive than Muse Spark Open ($1.25/1M tokens).

For output processing, Claude Sonnet 5.5 ($10.00/1M tokens) is 2.4x more expensive than Muse Spark Open ($4.25/1M tokens).

In conclusion, Claude Sonnet 5.5 is more expensive than Muse Spark Open.*

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

Lowest available price from all providers
Mon Oct 19 2026 • llm-stats.com
Anthropic
Claude Sonnet 5.5
Input tokens$2.00
Output tokens$10.00
Best providerAnthropic
Meta
Muse Spark Open
Input tokens$1.25
Output tokens$4.25
Best providerTogether
Notice missing or incorrect data?

Context Window

Maximum input and output token capacity

Muse Spark Open accepts 1,048,576 input tokens compared to Claude Sonnet 5.5's 1,000,000 tokens. Muse Spark Open can generate longer responses up to 1,048,576 tokens, while Claude Sonnet 5.5 is limited to 128,000 tokens.

Anthropic
Claude Sonnet 5.5
Input1,000,000 tokens
Output128,000 tokens
Meta
Muse Spark Open
Input1,048,576 tokens
Output1,048,576 tokens
Mon Oct 19 2026 • llm-stats.com

Input capabilities

Documented input modalities across available providers

Both Claude Sonnet 5.5 and Muse Spark Open 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

Muse Spark Open

Text
Images
Audio
Video

License

Usage and distribution terms

Claude Sonnet 5.5 is licensed under a proprietary license, while Muse Spark Open uses Muse Model License.

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

Claude Sonnet 5.5

Proprietary

Closed source

Muse Spark Open

Muse Model License

Open weights

Release Timeline

When each model was launched

Claude Sonnet 5.5 was released on 2026-09-28, while Muse Spark Open was released on 2026-10-15.

Muse Spark Open is 1 month newer than Claude Sonnet 5.5.

Claude Sonnet 5.5

Sep 28, 2026

3 weeks ago

Muse Spark Open

Oct 15, 2026

4 days ago

2w newer

Knowledge Cutoff

When training data ends

Claude Sonnet 5.5 has a documented knowledge cutoff of 2026-06-01, while Muse Spark Open'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 Muse Spark Open's cutoff date.

Claude Sonnet 5.5

Jun 2026

Muse Spark Open

—

Provider Availability

Claude Sonnet 5.5 is available from Anthropic. Muse Spark Open is available from Together.

Claude Sonnet 5.5

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

Muse Spark Open

together logo
Together
Input Price:Input: $1.25/1MOutput Price:Output: $4.25/1M
* 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 Muse Spark Open side-by-side, then vote on the output you prefer.

Claude Sonnet 5.5
✓ Preferred
Muse Spark Open
Open in Playground

FAQ

Common questions about Claude Sonnet 5.5 vs Muse Spark Open.

Which is better, Claude Sonnet 5.5 or Muse Spark Open?

Claude Sonnet 5.5 leads the LLM Stats Score 58.3 to 44.9. Claude Sonnet 5.5 is made by Anthropic and Muse Spark Open 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 Muse Spark Open 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%. Muse Spark Open scores MCP Atlas: 89.2%, GPQA: 89.0%, OSWorld-Verified: 80.4%, BabyVision: 80.2%, Terminal-Bench 2.1: 76.4%.

Is Claude Sonnet 5.5 cheaper than Muse Spark Open?

Muse Spark Open is 1.6x cheaper for input tokens. Claude Sonnet 5.5 costs $2.00/M input and $10.00/M output via anthropic. Muse Spark Open costs $1.25/M input and $4.25/M output via together.

What are the context window sizes for Claude Sonnet 5.5 and Muse Spark Open?

Claude Sonnet 5.5 supports 1.0M tokens and Muse Spark Open 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 Muse Spark Open?

Key differences include LLM Stats Score (58.3 vs 44.9), context window (1.0M vs 1.0M), input pricing ($2.00 vs $1.25/M), licensing (Proprietary vs Muse Model License). See the full comparison above for benchmark-by-benchmark results.

Who makes Claude Sonnet 5.5 and Muse Spark Open?

Claude Sonnet 5.5 is developed by Anthropic and Muse Spark Open is developed by Meta.

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