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Claude Sonnet 5.5 vs o1-preview

Claude Sonnet 5.5 leads the LLM Stats Score 58.1 to 16.6. Claude Sonnet 5.5 is 6.6x cheaper per token.

Anthropic · OpenAI · Updated for 2026

Which is better?

Claude Sonnet 5.5 leads the overall LLM Stats Score 58.1 to 16.6, ranking #3 overall.

On price, Claude Sonnet 5.5 is roughly 6.6x 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 58.1 and ranks #3 on LLM Stats
  • your work emphasizes reasoning and coding — it leads those capability indexes
  • cost matters — it's about 6.6x cheaper per token
  • 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 o1-preview

  • you want predictable pricing at $15.00/M input and $60.00/M output

At a glance

The differences that matter most.

Core performance indexes
58.1
#3
16.6
#227
56.6
#3
16.8
#220
48.9
#2
-3.2
#259
Cost, coverage & limits
Benchmark wins
—
—
Input price
$2.00 / M
$15.00 / M
Output price
$10.00 / M
$60.00 / M
Context window
1,000,000
128,000

Capability indexes

Additional strengths measured across groups of related public benchmarks

1 shared
Index
Claude Sonnet 5.5
o1-preview
36.9#34
20.2#163
Conservative TrueSkill rating · higher is betterHow scores work

Individual benchmarks

47 reported for Claude Sonnet 5.5 · 8 for o1-preview

No common benchmarks found

Claude Sonnet 5.5 and o1-previewdon'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

Claude Sonnet 5.5 costs less

For input processing, Claude Sonnet 5.5 ($2.00/1M tokens) is 7.5x cheaper than o1-preview ($15.00/1M tokens).

For output processing, Claude Sonnet 5.5 ($10.00/1M tokens) is 6.0x cheaper than o1-preview ($60.00/1M tokens).

In conclusion, o1-preview is more expensive than Claude Sonnet 5.5.*

* 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
OpenAI
o1-preview
Input tokens$15.00
Output tokens$60.00
Best providerOpenAI
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 o1-preview's 128,000 tokens. Claude Sonnet 5.5 can generate longer responses up to 128,000 tokens, while o1-preview is limited to 32,768 tokens.

Anthropic
Claude Sonnet 5.5
Input1,000,000 tokens
Output128,000 tokens
OpenAI
o1-preview
Input128,000 tokens
Output32,768 tokens
Tue Sep 29 2026 • llm-stats.com

Input capabilities

Documented input modalities across available providers

Claude Sonnet 5.5 supports multimodal inputs, whereas o1-preview 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

o1-preview

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

o1-preview

Proprietary

Closed source

Release Timeline

When each model was launched

Claude Sonnet 5.5 was released on 2026-09-28, while o1-preview was released on 2024-09-12.

Claude Sonnet 5.5 is 25 months newer than o1-preview.

Claude Sonnet 5.5

Sep 28, 2026

1 days ago

2.0yr newer
o1-preview

Sep 12, 2024

2.0 years ago

Knowledge Cutoff

When training data ends

Claude Sonnet 5.5 has a documented knowledge cutoff of 2026-06-01, while o1-preview'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 o1-preview's cutoff date.

Claude Sonnet 5.5

Jun 2026

o1-preview

—

Provider Availability

Claude Sonnet 5.5 is available from Anthropic. o1-preview is available from OpenAI, Azure.

Claude Sonnet 5.5

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

o1-preview

openai logo
OpenAI
Input Price:Input: $15.00/1MOutput Price:Output: $60.00/1M
azure logo
Azure
Input Price:Input: $16.50/1MOutput Price:Output: $66.00/1M
* 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 o1-preview side-by-side, then vote on the output you prefer.

Claude Sonnet 5.5
✓ Preferred
o1-preview
Open in Playground

FAQ

Common questions about Claude Sonnet 5.5 vs o1-preview.

Which is better, Claude Sonnet 5.5 or o1-preview?

Claude Sonnet 5.5 leads the LLM Stats Score 58.1 to 16.6. Claude Sonnet 5.5 is made by Anthropic and o1-preview is made by OpenAI. 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 o1-preview 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%. o1-preview scores MGSM: 90.8%, MMLU: 90.8%, MATH: 85.5%, GPQA: 73.3%, LiveBench: 52.3%.

Is Claude Sonnet 5.5 cheaper than o1-preview?

Claude Sonnet 5.5 is 7.5x cheaper for input tokens. Claude Sonnet 5.5 costs $2.00/M input and $10.00/M output via anthropic. o1-preview costs $15.00/M input and $60.00/M output via openai.

What are the context window sizes for Claude Sonnet 5.5 and o1-preview?

Claude Sonnet 5.5 supports 1.0M tokens and o1-preview 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 o1-preview?

Key differences include LLM Stats Score (58.1 vs 16.6), context window (1.0M vs 128K), input pricing ($2.00 vs $15.00/M), multimodal support (yes vs no). See the full comparison above for benchmark-by-benchmark results.

Who makes Claude Sonnet 5.5 and o1-preview?

Claude Sonnet 5.5 is developed by Anthropic and o1-preview is developed by OpenAI.