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Claude Sonnet 5.5 vs GPT-4o

Claude Sonnet 5.5 leads the LLM Stats Score 58.1 to 14.1. Claude Sonnet 5.5 is 1.1x cheaper per token.

Anthropic · OpenAI · Updated for 2026

Which is better?

Claude Sonnet 5.5 leads the overall LLM Stats Score 58.1 to 14.1, ranking #3 overall.

On price, Claude Sonnet 5.5 is roughly 1.1x 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 1.1x 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 GPT-4o

  • you want predictable pricing at $2.50/M input and $10.00/M output

At a glance

The differences that matter most.

Claude Sonnet 5.5
Anthropic
GPT-4o
OpenAI
Core performance indexes
LLM Stats Score
58.1
#3
14.1
#245
Reasoning
56.6
#3
15.9
#226
Coding
48.9
#2
-0.6
#252
Cost, coverage & limits
Benchmark wins
—
—
Input price
$2.00 / M
$2.50 / M
Output price
$10.00 / M
$10.00 / M
Context window
1,000,000
128,000

Capability indexes

Additional strengths measured across groups of related public benchmarks

4 shared
Index
Claude Sonnet 5.5
GPT-4o
Math
36.9#34
12.5#235
Vision
40.1#3
8.3#142
Tool use
33.9#2
5.5#156
Multimodal
40.2#2
12.0#113
Conservative TrueSkill rating · higher is betterHow scores work

Individual benchmarks

47 reported for Claude Sonnet 5.5 · 38 for GPT-4o

No common benchmarks found

Claude Sonnet 5.5 and GPT-4odon'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 1.3x cheaper than GPT-4o ($2.50/1M tokens).

For output processing, Claude Sonnet 5.5 ($10.00/1M tokens) costs the same as GPT-4o ($10.00/1M tokens).

In conclusion, GPT-4o 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
GPT-4o
Input tokens$2.50
Output tokens$10.00
Best providerAzure
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 GPT-4o's 128,000 tokens. Claude Sonnet 5.5 can generate longer responses up to 128,000 tokens, while GPT-4o is limited to 16,384 tokens.

Anthropic
Claude Sonnet 5.5
Input1,000,000 tokens
Output128,000 tokens
OpenAI
GPT-4o
Input128,000 tokens
Output16,384 tokens
Tue Sep 29 2026 • llm-stats.com

Input capabilities

Documented input modalities across available providers

Both Claude Sonnet 5.5 and GPT-4o 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

GPT-4o

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

GPT-4o

Proprietary

Closed source

Release Timeline

When each model was launched

Claude Sonnet 5.5 was released on 2026-09-28, while GPT-4o was released on 2024-08-06.

Claude Sonnet 5.5 is 26 months newer than GPT-4o.

Claude Sonnet 5.5

Sep 28, 2026

1 days ago

2.1yr newer
GPT-4o

Aug 6, 2024

2.1 years ago

Knowledge Cutoff

When training data ends

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

Claude Sonnet 5.5

Jun 2026

GPT-4o

—

Provider Availability

Claude Sonnet 5.5 is available from Anthropic. GPT-4o is available from Azure, OpenAI.

Claude Sonnet 5.5

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

GPT-4o

azure logo
Azure
Input Price:Input: $2.50/1MOutput Price:Output: $10.00/1M
openai logo
OpenAI
Input Price:Input: $2.50/1MOutput Price:Output: $10.00/1M
* 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 GPT-4o side-by-side, then vote on the output you prefer.

Claude Sonnet 5.5
✓ Preferred
GPT-4o
Open in Playground

FAQ

Common questions about Claude Sonnet 5.5 vs GPT-4o.

Which is better, Claude Sonnet 5.5 or GPT-4o?

Claude Sonnet 5.5 leads the LLM Stats Score 58.1 to 14.1. Claude Sonnet 5.5 is made by Anthropic and GPT-4o 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 GPT-4o 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%. GPT-4o scores AI2D: 94.2%, DocVQA: 92.8%, ChartQA: 85.7%, MMLU: 85.7%, CharXiv-D: 85.3%.

Is Claude Sonnet 5.5 cheaper than GPT-4o?

Claude Sonnet 5.5 is 1.3x cheaper for input tokens. Claude Sonnet 5.5 costs $2.00/M input and $10.00/M output via anthropic. GPT-4o costs $2.50/M input and $10.00/M output via azure.

What are the context window sizes for Claude Sonnet 5.5 and GPT-4o?

Claude Sonnet 5.5 supports 1.0M tokens and GPT-4o 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 GPT-4o?

Key differences include LLM Stats Score (58.1 vs 14.1), context window (1.0M vs 128K), input pricing ($2.00 vs $2.50/M). See the full comparison above for benchmark-by-benchmark results.

Who makes Claude Sonnet 5.5 and GPT-4o?

Claude Sonnet 5.5 is developed by Anthropic and GPT-4o is developed by OpenAI.

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