Head-to-head · Anthropic vs OpenAI
Claude Opus 5.5 vs GPT-6 Astra
Quick answer: Claude Opus 5.5 stands out for matches Claude Fable 5.1 on most work at a much lower price. GPT-6 Astra stands out for highest capability OpenAI offers. Reviewed September 2026.
Overview
Claude Opus 5.5: Claude Opus 5.5, released on 22 September 2026, is Anthropic's newest Opus model. Anthropic reports it performs at the level of Claude Fable 5.1 on most work while costing about 40% less to run than Opus 5, with a focus on agentic coding, computer use and knowledge work.
GPT-6 Astra: GPT-6 Astra, released by OpenAI on 3 September 2026, is the company's most capable model to date, with state-of-the-art results on computer use, coding, cybersecurity and science. It sits at the top of the GPT-6 family in both capability and price.
At a glance
| Dimension | Claude Opus 5.5 | GPT-6 Astra |
|---|---|---|
| Vendor | Anthropic | OpenAI |
| Starting price | API: $4 in / $20 out per M tokens | API: $10 in / $50 out per M tokens |
| Pricing model | Paid | Paid |
| Free tier | No | No |
| Category | Generative AI | Generative AI |
Strengths and limits
Claude Opus 5.5
- Matches Claude Fable 5.1 on most work at a much lower price
- Faster output than Opus 5
- Strong on coding and knowledge work such as financial analysis
Watch out for
- Newest release, so fewer independent long-term evaluations
- Output still costs $20 per million tokens
- Sonnet or Haiku are cheaper for routine tasks
GPT-6 Astra
- Highest capability OpenAI offers
- Broad strength across coding and agentic work
- Large ecosystem of tools and integrations
Watch out for
- $10 input and $50 output per million tokens
- GPT-6 Sol is far cheaper for most work
- Very new, so long-term evaluations are limited
Key features
Claude Opus 5.5
- 1M-token context window at standard pricing
- Agentic coding, code review and bug detection
- Computer use and complex multi-step tasks
- Clearer, more direct communication style
- Available in Claude apps, the API, Claude Code, AWS, Google Cloud and Microsoft Azure
GPT-6 Astra
- Top of the GPT-6 family for capability
- Strong computer use and coding performance
- Advanced cybersecurity and science reasoning
- Available through the OpenAI API
Pricing compared
Claude Opus 5.5 is priced by usage rather than by seat: API: $4 in / $20 out per M tokens. That means cost scales with how much text you send and receive, so estimate your monthly volume before committing.
GPT-6 Astra is priced by usage rather than by seat: API: $10 in / $50 out per M tokens. That means cost scales with how much text you send and receive, so estimate your monthly volume before committing.
Frequently asked questions
Which is better, Claude Opus 5.5 or GPT-6 Astra?
It depends on the work. Claude Opus 5.5 stands out for matches Claude Fable 5.1 on most work at a much lower price. GPT-6 Astra stands out for highest capability OpenAI offers.
How do Claude Opus 5.5 and GPT-6 Astra compare on price?
Claude Opus 5.5 is priced by usage rather than by seat: API: $4 in / $20 out per M tokens. That means cost scales with how much text you send and receive, so estimate your monthly volume before committing. GPT-6 Astra is priced by usage rather than by seat: API: $10 in / $50 out per M tokens. That means cost scales with how much text you send and receive, so estimate your monthly volume before committing.
Is there a free option between Claude Opus 5.5 and GPT-6 Astra?
Neither lists a permanent free tier. Look for trials or usage-based pricing to test on real work first.