Claude Sonnet 4.6 vs GPT-5.5 Instant
Claude Sonnet 4.6 and GPT-5.5 Instant are closely matched at 36.9 and 32.2 on the LLM Stats Score. Claude Sonnet 4.6 is 1.9x cheaper per token.
Anthropic · OpenAI · Updated for 2026
Which is better?
Claude Sonnet 4.6 and GPT-5.5 Instant are closely matched on the overall LLM Stats Score at 36.9 and 32.2.
The models split the 2 individual benchmarks reported for both models evenly.
On price, Claude Sonnet 4.6 is roughly 1.9x cheaper per token on a blended 3:1 input/output basis, which adds up quickly at production volume.
GPT-5.5 Instant also accepts a larger context window (400,000 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 4.6
- cost matters — it's about 1.9x cheaper per token
Choose GPT-5.5 Instant
- you process long inputs — it offers a 400,000 token context window
- you want the most recent training data — it shipped May 2026
At a glance
The differences that matter most.
Capability indexes
Additional strengths measured across groups of related public benchmarks
Individual benchmarks
17 reported for Claude Sonnet 4.6 · 9 for GPT-5.5 Instant
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.
Human preference
Blind head-to-head votes and playground preference scores
Pricing Analysis
Price comparison per million tokens
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
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.
Input capabilities
Documented input modalities across available providers
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
GPT-5.5 Instant
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 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.
Feb 17, 2026
7 months ago
May 5, 2026
5 months ago
2mo newerKnowledge 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.
—
Aug 2025
Provider Availability
Claude Sonnet 4.6 is available from Anthropic, DeepInfra. GPT-5.5 Instant is available from OpenAI.
Claude Sonnet 4.6
GPT-5.5 Instant
Outputs Comparison
Judge for yourself.
Run your own prompts against Claude Sonnet 4.6 and GPT-5.5 Instant side-by-side, then vote on the output you prefer.
FAQ
Common questions about Claude Sonnet 4.6 vs GPT-5.5 Instant.