Model Comparison

Claude Sonnet 5 vs GPT-5.5 ProWhich is better in 2026?

Both models are evenly matched across the benchmarks. Claude Sonnet 5 is 11.3x cheaper per token.

Verdict: Claude Sonnet 5 vs GPT-5.5 Pro — which is better?

Claude Sonnet 5 (by Anthropic) and GPT-5.5 Pro (by OpenAI) are two of the AI models people compare most. Here is how they stack up on benchmarks, price and capabilities, and which one to pick in 2026.

Claude Sonnet 5 outperforms in 1 benchmarks (Humanity's Last Exam), while GPT-5.5 Pro is better at 1 benchmark (BrowseComp). Both models are evenly matched across the benchmarks.

On price, Claude Sonnet 5 is roughly 11.3x cheaper per token on a blended 3:1 input/output basis, which adds up quickly at production volume.

GPT-5.5 Pro also accepts a larger context window (1,050,000 input tokens), making it the stronger choice for long documents and large codebases.

Choose Claude Sonnet 5 if…

  • cost matters — it's about 11.3x cheaper per token
  • you want the most recent training data — it shipped Jun 2026

Choose GPT-5.5 Pro if…

  • you process long inputs — it offers a 1,050,000 token context window

Performance Benchmarks

Comparative analysis across standard metrics

2 benchmarks

Claude Sonnet 5 outperforms in 1 benchmarks (Humanity's Last Exam), while GPT-5.5 Pro is better at 1 benchmark (BrowseComp).

Both models are evenly matched across the benchmarks.

Fri Jul 17 2026 • llm-stats.com

Arena Performance

Human preference votes

Pricing Analysis

Price comparison per million tokens

Claude Sonnet 5 costs less

For input processing, Claude Sonnet 5 ($3.00/1M tokens) is 10.0x cheaper than GPT-5.5 Pro ($30.00/1M tokens).

For output processing, Claude Sonnet 5 ($15.00/1M tokens) is 12.0x cheaper than GPT-5.5 Pro ($180.00/1M tokens).

In conclusion, GPT-5.5 Pro is more expensive than Claude Sonnet 5.*

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

Lowest available price from all providers
Fri Jul 17 2026 • llm-stats.com
Anthropic
Claude Sonnet 5
Input tokens$3.00
Output tokens$15.00
Best providerAnthropic
OpenAI
GPT-5.5 Pro
Input tokens$30.00
Output tokens$180.00
Best providerOpenAI
Notice missing or incorrect data?Start an Issue→

Context Window

Maximum input and output token capacity

GPT-5.5 Pro accepts 1,050,000 input tokens compared to Claude Sonnet 5's 1,000,000 tokens. GPT-5.5 Pro can generate longer responses up to 128,000 tokens, while Claude Sonnet 5 is limited to 64,000 tokens.

Anthropic
Claude Sonnet 5
Input1,000,000 tokens
Output64,000 tokens
OpenAI
GPT-5.5 Pro
Input1,050,000 tokens
Output128,000 tokens
Fri Jul 17 2026 • llm-stats.com

Input Capabilities

Supported data types and modalities

Both Claude Sonnet 5 and GPT-5.5 Pro support multimodal inputs.

They are both capable of processing various types of data, offering versatility in application.

Claude Sonnet 5

Text
Images
Audio
Video

GPT-5.5 Pro

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

Proprietary

Closed source

GPT-5.5 Pro

Proprietary

Closed source

Release Timeline

When each model was launched

Claude Sonnet 5 was released on 2026-06-30, while GPT-5.5 Pro was released on 2026-04-23.

Claude Sonnet 5 is 2 months newer than GPT-5.5 Pro.

Claude Sonnet 5

Jun 30, 2026

2 weeks ago

2mo newer
GPT-5.5 Pro

Apr 23, 2026

2 months ago

Knowledge Cutoff

When training data ends

GPT-5.5 Pro has a documented knowledge cutoff of 2025-12-01, while Claude Sonnet 5's cutoff date is not specified.

We can confirm GPT-5.5 Pro's training data extends to 2025-12-01, but cannot make a direct comparison without Claude Sonnet 5's cutoff date.

Claude Sonnet 5

—

GPT-5.5 Pro

Dec 2025

Provider Availability

Claude Sonnet 5 is available from Anthropic. GPT-5.5 Pro is available from OpenAI.

Claude Sonnet 5

anthropic logo
Anthropic
Input Price:Input: $3.00/1MOutput Price:Output: $15.00/1M

GPT-5.5 Pro

openai logo
OpenAI
Input Price:Input: $30.00/1MOutput Price:Output: $180.00/1M
* Prices shown are per million tokens

Outputs Comparison

Notice missing or incorrect data?Start an Issue discussion→

Key Takeaways

Anthropic
Less expensive input tokens
Less expensive output tokens
Higher Humanity's Last Exam score (57.4% vs 57.2%)
OpenAI
Larger context window (1,050,000 tokens)
Higher BrowseComp score (90.1% vs 84.7%)

Detailed Comparison

Interactive Arena

Judge for yourself.

Run your own prompts against Claude Sonnet 5 and GPT-5.5 Pro side-by-side, then vote on the output you prefer.

Claude Sonnet 5
✓ Preferred
GPT-5.5 Pro
Open in Playground
AI Model Comparison Table
Feature
Anthropic
Claude Sonnet 5
OpenAI
GPT-5.5 Pro

FAQ

Common questions about Claude Sonnet 5 vs GPT-5.5 Pro.

Which is better, Claude Sonnet 5 or GPT-5.5 Pro?

Both models are evenly matched across the benchmarks. Claude Sonnet 5 is made by Anthropic and GPT-5.5 Pro is made by OpenAI. The best choice depends on your use case — compare their benchmark scores, pricing, and capabilities above.

How does Claude Sonnet 5 compare to GPT-5.5 Pro in benchmarks?

Claude Sonnet 5 scores CharXiv-R: 88.3%, ChartMuseum: 86.7%, SWE-Bench Verified: 85.2%, BrowseComp: 84.7%, GDP.pdf: 81.6%. GPT-5.5 Pro scores BrowseComp: 90.1%, GDPval-MM: 82.3%, Humanity's Last Exam: 57.2%, FrontierMath: 39.6%, GeneBench: 33.2%.

Is Claude Sonnet 5 cheaper than GPT-5.5 Pro?

Claude Sonnet 5 is 10.0x cheaper for input tokens. Claude Sonnet 5 costs $3.00/M input and $15.00/M output via anthropic. GPT-5.5 Pro costs $30.00/M input and $180.00/M output via openai.

What are the context window sizes for Claude Sonnet 5 and GPT-5.5 Pro?

Claude Sonnet 5 supports 1.0M tokens and GPT-5.5 Pro supports 1.1M 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 and GPT-5.5 Pro?

Key differences include context window (1.0M vs 1.1M), input pricing ($3.00 vs $30.00/M). See the full comparison above for benchmark-by-benchmark results.

Who makes Claude Sonnet 5 and GPT-5.5 Pro?

Claude Sonnet 5 is developed by Anthropic and GPT-5.5 Pro is developed by OpenAI.

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