Claude Sonnet 5.5 vs GPT-5.1 High
Claude Sonnet 5.5 leads the LLM Stats Score 58.1 to 35.2. GPT-5.1 High is 1.2x cheaper per token.
Anthropic · OpenAI · Updated for 2026
Which is better?
Claude Sonnet 5.5 leads the overall LLM Stats Score 58.1 to 35.2, ranking #3 overall.
On price, GPT-5.1 High is roughly 1.2x 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 — it leads those capability indexes
- 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-5.1 High
- cost matters — it's about 1.2x cheaper per token
At a glance
The differences that matter most.
Capability indexes
Additional strengths measured across groups of related public benchmarks
Individual benchmarks
47 reported for Claude Sonnet 5.5 · 3 for GPT-5.1 High
Claude Sonnet 5.5 and GPT-5.1 Highdon'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
For input processing, Claude Sonnet 5.5 ($2.00/1M tokens) is 1.6x more expensive than GPT-5.1 High ($1.25/1M tokens).
For output processing, Claude Sonnet 5.5 ($10.00/1M tokens) costs the same as GPT-5.1 High ($10.00/1M tokens).
In conclusion, Claude Sonnet 5.5 is more expensive than GPT-5.1 High.*
* Using a 3:1 ratio of input to output tokens
Context Window
Maximum input and output token capacity
Claude Sonnet 5.5 accepts 1,000,000 input tokens compared to GPT-5.1 High's 400,000 tokens. Both models can generate responses up to 128,000 tokens.
Input capabilities
Documented input modalities across available providers
Both Claude Sonnet 5.5 and GPT-5.1 High support multimodal inputs.
They are both capable of processing various types of data, offering versatility in application.
Claude Sonnet 5.5
GPT-5.1 High
License
Usage and distribution terms
Both models are licensed under proprietary licenses.
Both models have usage restrictions defined by their respective organizations.
Proprietary
Closed source
Proprietary
Closed source
Release Timeline
When each model was launched
Claude Sonnet 5.5 was released on 2026-09-28, while GPT-5.1 High was released on 2025-11-12.
Claude Sonnet 5.5 is 11 months newer than GPT-5.1 High.
Sep 28, 2026
1 days ago
10mo newerNov 12, 2025
10 months ago
Knowledge Cutoff
When training data ends
Claude Sonnet 5.5 has a documented knowledge cutoff of 2026-06-01, while GPT-5.1 High'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-5.1 High's cutoff date.
Jun 2026
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Provider Availability
Claude Sonnet 5.5 is available from Anthropic. GPT-5.1 High is available from OpenAI.
Claude Sonnet 5.5
GPT-5.1 High
Outputs Comparison
Judge for yourself.
Run your own prompts against Claude Sonnet 5.5 and GPT-5.1 High side-by-side, then vote on the output you prefer.
FAQ
Common questions about Claude Sonnet 5.5 vs GPT-5.1 High.