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Claude Sonnet 5.5 vs Solar Pro 4

Claude Sonnet 5.5 leads the LLM Stats Score 58.0 to 35.1. Solar Pro 4 is 7.6x cheaper per token.

Anthropic · Upstage · Updated for 2026

Which is better?

Claude Sonnet 5.5 leads the overall LLM Stats Score 58.0 to 35.1, ranking #3 overall.

On price, Solar Pro 4 is roughly 7.6x 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 58.0 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 Solar Pro 4

  • cost matters — it's about 7.6x cheaper per token

At a glance

The differences that matter most.

Claude Sonnet 5.5
Anthropic
Solar Pro 4
Upstage
Core performance indexes
LLM Stats Score
58.0
#3
35.1
#96
Reasoning
56.6
#3
34.7
#91
Coding
48.8
#2
21.0
#99
Agents
42.3
#3
11.5
#115
Cost, coverage & limits
Benchmark wins
—
—
Input price
$2.00 / M
$0.30 / M
Output price
$10.00 / M
$1.20 / M
Context window
1,000,000
524,288

Capability indexes

Additional strengths measured across groups of related public benchmarks

2 shared
Index
Claude Sonnet 5.5
Solar Pro 4
Math
36.9#34
32.3#61
Tool use
34.0#2
8.7#141
Conservative TrueSkill rating · higher is betterHow scores work

Individual benchmarks

47 reported for Claude Sonnet 5.5 · 9 for Solar Pro 4

No common benchmarks found

Claude Sonnet 5.5 and Solar Pro 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

Solar Pro 4 costs less

For input processing, Claude Sonnet 5.5 ($2.00/1M tokens) is 6.7x more expensive than Solar Pro 4 ($0.30/1M tokens).

For output processing, Claude Sonnet 5.5 ($10.00/1M tokens) is 8.3x more expensive than Solar Pro 4 ($1.20/1M tokens).

In conclusion, Claude Sonnet 5.5 is more expensive than Solar Pro 4.*

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

Lowest available price from all providers
Wed Oct 07 2026 • llm-stats.com
Anthropic
Claude Sonnet 5.5
Input tokens$2.00
Output tokens$10.00
Best providerAnthropic
Upstage
Solar Pro 4
Input tokens$0.30
Output tokens$1.20
Best providerUnknown Organization
Notice missing or incorrect data?

Context Window

Maximum input and output token capacity

Claude Sonnet 5.5 accepts 1,000,000 input tokens compared to Solar Pro 4's 524,288 tokens. Solar Pro 4 can generate longer responses up to 131,072 tokens, while Claude Sonnet 5.5 is limited to 128,000 tokens.

Anthropic
Claude Sonnet 5.5
Input1,000,000 tokens
Output128,000 tokens
Upstage
Solar Pro 4
Input524,288 tokens
Output131,072 tokens
Wed Oct 07 2026 • llm-stats.com

Input capabilities

Documented input modalities across available providers

Claude Sonnet 5.5 supports multimodal inputs, whereas Solar Pro 4 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

Solar Pro 4

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

Solar Pro 4

Proprietary

Closed source

Release Timeline

When each model was launched

Claude Sonnet 5.5 was released on 2026-09-28, while Solar Pro 4 was released on 2026-08-06.

Claude Sonnet 5.5 is 2 months newer than Solar Pro 4.

Claude Sonnet 5.5

Sep 28, 2026

1 weeks ago

1mo newer
Solar Pro 4

Aug 6, 2026

2 months ago

Knowledge Cutoff

When training data ends

Claude Sonnet 5.5 has a documented knowledge cutoff of 2026-06-01, while Solar Pro 4'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 Solar Pro 4's cutoff date.

Claude Sonnet 5.5

Jun 2026

Solar Pro 4

—

Provider Availability

Claude Sonnet 5.5 is available from Anthropic. Solar Pro 4 is available from Upstage.

Claude Sonnet 5.5

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

Solar Pro 4

upstage logo
Unknown Organization
Input Price:Input: $0.30/1MOutput Price:Output: $1.20/1M
* 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 Solar Pro 4 side-by-side, then vote on the output you prefer.

Claude Sonnet 5.5
✓ Preferred
Solar Pro 4
Open in Playground

FAQ

Common questions about Claude Sonnet 5.5 vs Solar Pro 4.

Which is better, Claude Sonnet 5.5 or Solar Pro 4?

Claude Sonnet 5.5 leads the LLM Stats Score 58.0 to 35.1. Claude Sonnet 5.5 is made by Anthropic and Solar Pro 4 is made by Upstage. 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 Solar Pro 4 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%. Solar Pro 4 scores AIME 2026: 95.3%, GPQA: 89.0%, LiveCodeBench: 87.8%, MMLU-Pro: 86.3%, AA-LCR: 71.0%.

Is Claude Sonnet 5.5 cheaper than Solar Pro 4?

Solar Pro 4 is 6.7x cheaper for input tokens. Claude Sonnet 5.5 costs $2.00/M input and $10.00/M output via anthropic. Solar Pro 4 costs $0.30/M input and $1.20/M output via upstage.

What are the context window sizes for Claude Sonnet 5.5 and Solar Pro 4?

Claude Sonnet 5.5 supports 1.0M tokens and Solar Pro 4 supports 524K 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 Solar Pro 4?

Key differences include LLM Stats Score (58.0 vs 35.1), context window (1.0M vs 524K), input pricing ($2.00 vs $0.30/M), multimodal support (yes vs no). See the full comparison above for benchmark-by-benchmark results.

Who makes Claude Sonnet 5.5 and Solar Pro 4?

Claude Sonnet 5.5 is developed by Anthropic and Solar Pro 4 is developed by Upstage.

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