Model Comparison

Claude Sonnet 4.6 vs GPT-5.5 Instant

Both models are evenly matched across the benchmarks. Claude Sonnet 4.6 is 1.9x cheaper per token.

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Performance Benchmarks

Comparative analysis across standard metrics

2 benchmarks

Claude Sonnet 4.6 outperforms in 1 benchmarks (GPQA), while GPT-5.5 Instant is better at 1 benchmark (MMMU-Pro).

Both models are evenly matched across the benchmarks.

Wed May 06 2026 • llm-stats.com

Arena Performance

Human preference votes

Pricing Analysis

Price comparison per million tokens

Claude Sonnet 4.6 costs less

For input processing, Claude Sonnet 4.6 ($3.00/1M tokens) is 1.7x cheaper than GPT-5.5 Instant ($5.00/1M tokens).

For output processing, Claude Sonnet 4.6 ($15.00/1M tokens) is 2.0x cheaper than GPT-5.5 Instant ($30.00/1M tokens).

In conclusion, GPT-5.5 Instant is more expensive than Claude Sonnet 4.6.*

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

Lowest available price from all providers
Wed May 06 2026 • llm-stats.com
Anthropic
Claude Sonnet 4.6
Input tokens$3.00
Output tokens$15.00
Best providerAnthropic
OpenAI
GPT-5.5 Instant
Input tokens$5.00
Output tokens$30.00
Best providerOpenAI
Notice missing or incorrect data?Start an Issue→

Context Window

Maximum input and output token capacity

GPT-5.5 Instant accepts 400,000 input tokens compared to Claude Sonnet 4.6's 200,000 tokens. GPT-5.5 Instant can generate longer responses up to 128,000 tokens, while Claude Sonnet 4.6 is limited to 64,000 tokens.

Anthropic
Claude Sonnet 4.6
Input200,000 tokens
Output64,000 tokens
OpenAI
GPT-5.5 Instant
Input400,000 tokens
Output128,000 tokens
Wed May 06 2026 • llm-stats.com

Input Capabilities

Supported data types and modalities

Both Claude Sonnet 4.6 and GPT-5.5 Instant support multimodal inputs.

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

Claude Sonnet 4.6

Text
Images
Audio
Video

GPT-5.5 Instant

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 4.6

Proprietary

Closed source

GPT-5.5 Instant

Proprietary

Closed source

Release Timeline

When each model was launched

Claude Sonnet 4.6 was released on 2026-02-17, while GPT-5.5 Instant was released on 2026-05-05.

GPT-5.5 Instant is 3 months newer than Claude Sonnet 4.6.

Claude Sonnet 4.6

Feb 17, 2026

2 months ago

GPT-5.5 Instant

May 5, 2026

1 days ago

2mo newer

Knowledge Cutoff

When training data ends

GPT-5.5 Instant has a documented knowledge cutoff of 2025-08-31, while Claude Sonnet 4.6's cutoff date is not specified.

We can confirm GPT-5.5 Instant's training data extends to 2025-08-31, but cannot make a direct comparison without Claude Sonnet 4.6's cutoff date.

Claude Sonnet 4.6

—

GPT-5.5 Instant

Aug 2025

Provider Availability

Claude Sonnet 4.6 is available from Anthropic. GPT-5.5 Instant is available from OpenAI.

Claude Sonnet 4.6

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

GPT-5.5 Instant

openai logo
OpenAI
Input Price:Input: $5.00/1MOutput Price:Output: $30.00/1M
* 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 GPQA score (89.9% vs 85.6%)
OpenAI
Larger context window (400,000 tokens)
Higher MMMU-Pro score (76.0% vs 75.6%)

Detailed Comparison

AI Model Comparison Table
Feature
Anthropic
Claude Sonnet 4.6
OpenAI
GPT-5.5 Instant

FAQ

Common questions about Claude Sonnet 4.6 vs GPT-5.5 Instant.

Which is better, Claude Sonnet 4.6 or GPT-5.5 Instant?

Both models are evenly matched across the benchmarks. Claude Sonnet 4.6 is made by Anthropic and GPT-5.5 Instant is made by OpenAI. The best choice depends on your use case — compare their benchmark scores, pricing, and capabilities above.

How does Claude Sonnet 4.6 compare to GPT-5.5 Instant in benchmarks?

Claude Sonnet 4.6 scores Tau2 Telecom: 97.9%, Tau2 Retail: 91.7%, GPQA: 89.9%, MMMLU: 89.3%, SWE-Bench Verified: 79.6%. GPT-5.5 Instant scores HealthBench Consensus: 94.7%, OmniDocBench 1.5: 87.5%, GPQA: 85.6%, CharXiv-R: 81.6%, AIME 2025: 81.2%.

Is Claude Sonnet 4.6 cheaper than GPT-5.5 Instant?

Claude Sonnet 4.6 is 1.7x cheaper for input tokens. Claude Sonnet 4.6 costs $3.00/M input and $15.00/M output via anthropic. GPT-5.5 Instant costs $5.00/M input and $30.00/M output via openai.

What are the context window sizes for Claude Sonnet 4.6 and GPT-5.5 Instant?

Claude Sonnet 4.6 supports 200K tokens and GPT-5.5 Instant supports 400K 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 4.6 and GPT-5.5 Instant?

Key differences include context window (200K vs 400K), input pricing ($3.00 vs $5.00/M). See the full comparison above for benchmark-by-benchmark results.

Who makes Claude Sonnet 4.6 and GPT-5.5 Instant?

Claude Sonnet 4.6 is developed by Anthropic and GPT-5.5 Instant is developed by OpenAI.