Model Comparison

Claude 3.5 Sonnet vs GPT-5.1 Instant

GPT-5.1 Instant significantly outperforms across most benchmarks. GPT-5.1 Instant is 1.7x cheaper per token.

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Performance Benchmarks

Comparative analysis across standard metrics

1 benchmarks

Claude 3.5 Sonnet outperforms in 0 benchmarks, while GPT-5.1 Instant is better at 1 benchmark (GPQA).

GPT-5.1 Instant significantly outperforms across most benchmarks.

Thu Apr 16 2026 • llm-stats.com

Arena Performance

Human preference votes

Pricing Analysis

Price comparison per million tokens

GPT-5.1 Instant costs less

For input processing, Claude 3.5 Sonnet ($3.00/1M tokens) is 2.4x more expensive than GPT-5.1 Instant ($1.25/1M tokens).

For output processing, Claude 3.5 Sonnet ($15.00/1M tokens) is 1.5x more expensive than GPT-5.1 Instant ($10.00/1M tokens).

In conclusion, Claude 3.5 Sonnet is more expensive than GPT-5.1 Instant.*

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

Lowest available price from all providers
Thu Apr 16 2026 • llm-stats.com
Anthropic
Claude 3.5 Sonnet
Input tokens$3.00
Output tokens$15.00
Best providerAWS Bedrock
OpenAI
GPT-5.1 Instant
Input tokens$1.25
Output tokens$10.00
Best providerOpenAI
Notice missing or incorrect data?Start an Issue→

Context Window

Maximum input and output token capacity

GPT-5.1 Instant accepts 400,000 input tokens compared to Claude 3.5 Sonnet's 200,000 tokens. Claude 3.5 Sonnet can generate longer responses up to 200,000 tokens, while GPT-5.1 Instant is limited to 128,000 tokens.

Anthropic
Claude 3.5 Sonnet
Input200,000 tokens
Output200,000 tokens
OpenAI
GPT-5.1 Instant
Input400,000 tokens
Output128,000 tokens
Thu Apr 16 2026 • llm-stats.com

Input Capabilities

Supported data types and modalities

Both Claude 3.5 Sonnet and GPT-5.1 Instant support multimodal inputs.

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

Claude 3.5 Sonnet

Text
Images
Audio
Video

GPT-5.1 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 3.5 Sonnet

Proprietary

Closed source

GPT-5.1 Instant

Proprietary

Closed source

Release Timeline

When each model was launched

Claude 3.5 Sonnet was released on 2024-06-21, while GPT-5.1 Instant was released on 2025-11-12.

GPT-5.1 Instant is 17 months newer than Claude 3.5 Sonnet.

Claude 3.5 Sonnet

Jun 21, 2024

1.8 years ago

GPT-5.1 Instant

Nov 12, 2025

5 months ago

1.4yr newer

Knowledge Cutoff

When training data ends

Neither model specifies a knowledge cutoff date.

Unable to compare the recency of their training data.

No cutoff dates available

Provider Availability

Claude 3.5 Sonnet is available from Bedrock, Google. GPT-5.1 Instant is available from OpenAI.

Claude 3.5 Sonnet

bedrock logo
AWS Bedrock
Input Price:Input: $3.00/1MOutput Price:Output: $15.00/1M
google logo
Google
Input Price:Input: $3.00/1MOutput Price:Output: $15.00/1M

GPT-5.1 Instant

openai logo
OpenAI
Input Price:Input: $1.25/1MOutput Price:Output: $10.00/1M
* Prices shown are per million tokens

Outputs Comparison

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Key Takeaways

Anthropic
OpenAI
Larger context window (400,000 tokens)
Less expensive input tokens
Less expensive output tokens
Higher GPQA score (88.1% vs 59.4%)
AnthropicClaude 3.5 Sonnet
OpenAIGPT-5.1 Instant
Compare in Playground

Detailed Comparison

AI Model Comparison Table
Feature
Anthropic
Claude 3.5 Sonnet
OpenAI
GPT-5.1 Instant

FAQ

Common questions about Claude 3.5 Sonnet vs GPT-5.1 Instant

GPT-5.1 Instant significantly outperforms across most benchmarks. Claude 3.5 Sonnet is made by Anthropic and GPT-5.1 Instant is made by OpenAI. The best choice depends on your use case — compare their benchmark scores, pricing, and capabilities above.
Claude 3.5 Sonnet scores GSM8k: 96.4%, BIG-Bench Hard: 93.1%, HumanEval: 92.0%, MGSM: 91.6%, MMLU: 90.4%. GPT-5.1 Instant scores Tau2 Telecom: 95.6%, AIME 2025: 94.0%, BrowseComp Long Context 128k: 90.0%, GPQA: 88.1%, MMMU: 85.4%.
GPT-5.1 Instant is 2.4x cheaper for input tokens. Claude 3.5 Sonnet costs $3.00/M input and $15.00/M output via bedrock. GPT-5.1 Instant costs $1.25/M input and $10.00/M output via openai.
Claude 3.5 Sonnet supports 200K tokens and GPT-5.1 Instant supports 400K tokens. A larger context window lets you process longer documents, conversations, or codebases in a single request.
Key differences include context window (200K vs 400K), input pricing ($3.00 vs $1.25/M). See the full comparison above for benchmark-by-benchmark results.
Claude 3.5 Sonnet is developed by Anthropic and GPT-5.1 Instant is developed by OpenAI.