Claude Opus 5.5 vs GPT-6 Astra
Claude Opus 5.5 and GPT-6 Astra are closely matched at 59.7 and 59.5 on the LLM Stats Score. Claude Opus 5.5 is 2.5x cheaper per token.
Anthropic · OpenAI · Updated for 2026
Which is better?
Claude Opus 5.5 and GPT-6 Astra are closely matched on the overall LLM Stats Score at 59.7 and 59.5.
In the 9 individual benchmarks reported for both models, Claude Opus 5.5 wins 7; this is a narrower head-to-head signal than the composite indexes.
On price, Claude Opus 5.5 is roughly 2.5x cheaper per token on a blended 3:1 input/output basis, which adds up quickly at production volume.
GPT-6 Astra also accepts a larger context window (1,050,000 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 Opus 5.5
- you value its reported benchmark strengths — it wins 7 of 9 exact shared results
- cost matters — it's about 2.5x cheaper per token
- you want the most recent training data — it shipped Sep 2026
Choose GPT-6 Astra
- you process long inputs — it offers a 1,050,000 token context window
At a glance
The differences that matter most.
Capability indexes
Additional strengths measured across groups of related public benchmarks
Individual benchmarks
31 reported for Claude Opus 5.5 · 22 for GPT-6 Astra
Claude Opus 5.5 outperforms in 7 benchmarks (BenchCAD (with Python tool), DeepSWE 1.1, FrontierCode 1.1, HealthBench Professional, Humanity's Last Exam (with tools, text-only), OSWorld 2.0, Terminal-Bench 4.0), while GPT-6 Astra is better at 2 benchmarks (AutomationBench, Terminal-Bench-Science 0.1).
Claude Opus 5.5 significantly outperforms across most benchmarks.
Human preference
Blind head-to-head votes and playground preference scores
Pricing Analysis
Price comparison per million tokens
For input processing, Claude Opus 5.5 ($4.00/1M tokens) is 2.5x cheaper than GPT-6 Astra ($10.00/1M tokens).
For output processing, Claude Opus 5.5 ($20.00/1M tokens) is 2.5x cheaper than GPT-6 Astra ($50.00/1M tokens).
In conclusion, GPT-6 Astra is more expensive than Claude Opus 5.5.*
* Using a 3:1 ratio of input to output tokens
Context Window
Maximum input and output token capacity
GPT-6 Astra accepts 1,050,000 input tokens compared to Claude Opus 5.5's 1,000,000 tokens. Both models can generate responses up to 128,000 tokens.
Input capabilities
Documented input modalities across available providers
Both Claude Opus 5.5 and GPT-6 Astra support multimodal inputs.
They are both capable of processing various types of data, offering versatility in application.
Claude Opus 5.5
GPT-6 Astra
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 Opus 5.5 was released on 2026-09-22, while GPT-6 Astra was released on 2026-09-04.
Claude Opus 5.5 is 1 month newer than GPT-6 Astra.
Sep 22, 2026
0 days ago
2w newerSep 4, 2026
2 weeks ago
Knowledge Cutoff
When training data ends
Claude Opus 5.5 has a knowledge cutoff of 2026-06-01, while GPT-6 Astra has a cutoff of 2026-04-30.
Claude Opus 5.5 has more recent training data (up to 2026-06-01), making it potentially better informed about events through that date compared to GPT-6 Astra (2026-04-30).
Jun 2026
2 mo newerApr 2026
Provider Availability
Claude Opus 5.5 is available from Anthropic. GPT-6 Astra is available from OpenAI.
Claude Opus 5.5
GPT-6 Astra
Outputs Comparison
Judge for yourself.
Run your own prompts against Claude Opus 5.5 and GPT-6 Astra side-by-side, then vote on the output you prefer.
FAQ
Common questions about Claude Opus 5.5 vs GPT-6 Astra.