Model Comparison

Claude Sonnet 5 vs GPT-5.6 LunaWhich is better in 2026?

Claude Sonnet 5 shows notably better performance in the majority of benchmarks. GPT-5.6 Luna is 2.7x cheaper per token.

Verdict: Claude Sonnet 5 vs GPT-5.6 Luna — which is better?

Claude Sonnet 5 (by Anthropic) and GPT-5.6 Luna (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 6 benchmarks (BrowseComp, GDP.pdf, GDPval-AA, HealthBench Professional, SWE-Bench Pro, Toolathlon), while GPT-5.6 Luna is better at 2 benchmarks (AutomationBench, BenchCAD). Claude Sonnet 5 shows notably better performance in the majority of benchmarks.

On price, GPT-5.6 Luna is roughly 2.7x cheaper per token on a blended 3:1 input/output basis, which adds up quickly at production volume.

GPT-5.6 Luna 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…

  • you want the strongest raw capability — it leads on 6 of 8 shared benchmarks

Choose GPT-5.6 Luna if…

  • cost matters — it's about 2.7x cheaper per token
  • you process long inputs — it offers a 1,050,000 token context window
  • you want the most recent training data — it shipped Jul 2026

Performance Benchmarks

Comparative analysis across standard metrics

8 benchmarks

Claude Sonnet 5 outperforms in 6 benchmarks (BrowseComp, GDP.pdf, GDPval-AA, HealthBench Professional, SWE-Bench Pro, Toolathlon), while GPT-5.6 Luna is better at 2 benchmarks (AutomationBench, BenchCAD).

Claude Sonnet 5 shows notably better performance in the majority of benchmarks.

Fri Jul 17 2026 • llm-stats.com

Arena Performance

Human preference votes

Pricing Analysis

Price comparison per million tokens

GPT-5.6 Luna costs less

For input processing, Claude Sonnet 5 ($3.00/1M tokens) is 3.0x more expensive than GPT-5.6 Luna ($1.00/1M tokens).

For output processing, Claude Sonnet 5 ($15.00/1M tokens) is 2.5x more expensive than GPT-5.6 Luna ($6.00/1M tokens).

In conclusion, Claude Sonnet 5 is more expensive than GPT-5.6 Luna.*

* 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-5.6 Luna
Input tokens$1.00
Output tokens$6.00
Best providerOpenAI
Notice missing or incorrect data?Start an Issue→

Context Window

Maximum input and output token capacity

GPT-5.6 Luna accepts 1,050,000 input tokens compared to Claude Sonnet 5's 1,000,000 tokens. GPT-5.6 Luna 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-5.6 Luna
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-5.6 Luna 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-5.6 Luna

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-5.6 Luna

Proprietary

Closed source

Release Timeline

When each model was launched

Claude Sonnet 5 was released on 2026-06-30, while GPT-5.6 Luna was released on 2026-07-09.

GPT-5.6 Luna is 0 month newer than Claude Sonnet 5.

Claude Sonnet 5

Jun 30, 2026

2 weeks ago

GPT-5.6 Luna

Jul 9, 2026

1 weeks ago

1w newer

Knowledge Cutoff

When training data ends

GPT-5.6 Luna has a documented knowledge cutoff of 2026-02-16, while Claude Sonnet 5's cutoff date is not specified.

We can confirm GPT-5.6 Luna's training data extends to 2026-02-16, but cannot make a direct comparison without Claude Sonnet 5's cutoff date.

Claude Sonnet 5

—

GPT-5.6 Luna

Feb 2026

Provider Availability

Claude Sonnet 5 is available from Anthropic. GPT-5.6 Luna is available from OpenAI.

Claude Sonnet 5

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

GPT-5.6 Luna

openai logo
OpenAI
Input Price:Input: $1.00/1MOutput Price:Output: $6.00/1M
* Prices shown are per million tokens

Outputs Comparison

Notice missing or incorrect data?Start an Issue discussion→

Key Takeaways

Anthropic
Higher BrowseComp score (84.7% vs 83.3%)
Higher GDP.pdf score (81.6% vs 22.7%)
Higher GDPval-AA score (53.9% vs 53.1%)
Higher HealthBench Professional score (57.8% vs 55.7%)
Higher SWE-Bench Pro score (63.2% vs 62.7%)
Higher Toolathlon score (54.3% vs 53.4%)
OpenAI
Larger context window (1,050,000 tokens)
Less expensive input tokens
Less expensive output tokens
Higher AutomationBench score (14.9% vs 13.5%)
Higher BenchCAD score (63.1% vs 37.3%)

Detailed Comparison

Interactive Arena

Judge for yourself.

Run your own prompts against Claude Sonnet 5 and GPT-5.6 Luna side-by-side, then vote on the output you prefer.

Claude Sonnet 5
✓ Preferred
GPT-5.6 Luna
Open in Playground
AI Model Comparison Table
Feature
Anthropic
Claude Sonnet 5
OpenAI
GPT-5.6 Luna

FAQ

Common questions about Claude Sonnet 5 vs GPT-5.6 Luna.

Which is better, Claude Sonnet 5 or GPT-5.6 Luna?

Claude Sonnet 5 shows notably better performance in the majority of benchmarks. Claude Sonnet 5 is made by Anthropic and GPT-5.6 Luna 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-5.6 Luna 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-5.6 Luna scores Connectors: 99.9%, HealthBench Consensus: 95.1%, GPQA: 92.3%, Search and Function-Calling: 89.7%, Capture-the-Flag Challenges (Internal): 85.2%.

Is Claude Sonnet 5 cheaper than GPT-5.6 Luna?

GPT-5.6 Luna is 3.0x cheaper for input tokens. Claude Sonnet 5 costs $3.00/M input and $15.00/M output via anthropic. GPT-5.6 Luna costs $1.00/M input and $6.00/M output via openai.

What are the context window sizes for Claude Sonnet 5 and GPT-5.6 Luna?

Claude Sonnet 5 supports 1.0M tokens and GPT-5.6 Luna 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-5.6 Luna?

Key differences include context window (1.0M vs 1.1M), input pricing ($3.00 vs $1.00/M). See the full comparison above for benchmark-by-benchmark results.

Who makes Claude Sonnet 5 and GPT-5.6 Luna?

Claude Sonnet 5 is developed by Anthropic and GPT-5.6 Luna is developed by OpenAI.

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