Claude Opus 5.5 vs GPT-6 Astra
Anthropic's Claude Opus 5.5 and OpenAI's GPT-6 Astra, compared on the figures Alevr runs on: list prices, context window, speed and intelligence grades, and the plan that includes each.
Anthropic
Claude Opus 5.5
Anthropic's newest Opus: long-running agentic coding and knowledge work, always thinking.
- Input / output per M
- $4.00 / $20.00
- Context
- 1M
- In Alevr from
- Pro
OpenAI
GPT-6 Astra
OpenAI's most capable model: built for hard end-to-end reasoning, coding, research, and computer-use work.
- Input / output per M
- $10.00 / $50.00
- Context
- 1.05M
- In Alevr from
- Pro
Side by side.
| Claude Opus 5.5 | GPT-6 Astra | |
|---|---|---|
| Lab | Anthropic | OpenAI |
| Released | Sep 2026 | Sep 2026 |
| Context window | 1,000,000 tokens | 1,050,000 tokens |
| Input, per M tokens | $4.00 | $10.00 |
| Cached input, per M tokens | $0.20 | $1.00 |
| Output, per M tokens | $20.00 | $50.00 |
| Intelligence grade | 9 / 10Catalog estimate | 10 / 10Catalog estimate |
| Speed grade | 4 / 10Catalog estimate | 4 / 10Catalog estimate |
| Adjustable thinking | Yes | Yes |
| Reads images | Yes | Yes |
| Searches the web in Alevr | Yes | Yes |
| Drives agents and Code | Yes | Yes |
| Included in Alevr from | Pro€24 a month incl. VAT | Pro€24 a month incl. VAT |
Which to pick.
Each answer below is a comparison of the figures above, nothing more. Costs use a chat turn of 800 input and 500 output tokens.
- For the lowest cost per messageClaude Opus 5.5
- At list prices, 1,000 requests of a chat turn of 800 input and 500 output tokens cost $13.20 on Claude Opus 5.5 and $33.00 on GPT-6 Astra. Claude Opus 5.5 is about 2.5× cheaper for this workload.
- For the hardest reasoningGPT-6 Astra
- GPT-6 Astra has the higher intelligence grade, 10 against 9 out of 10. Neither model has an Artificial Analysis measurement in Alevr's latest benchmark sync yet, so both grades are the catalog's estimates and may move when one lands.
- For quick back-and-forthNo clear difference
- Both carry the same speed grade, 4 out of 10.
- For long documentsNo clear difference
- The context windows are close: 1M and 1.05M tokens.
- On a smaller Alevr planNo clear difference
- Both are included from Pro, €24 a month incl. VAT.
Pick Claude Opus 5.5
- for the lowest cost per message
Pick GPT-6 Astra
- for the hardest reasoning
Use both in Alevr.
Alevr puts Claude, GPT, Gemini and 150+ models in one subscription, hosted in France. Both of these are included from Pro, €24 a month incl. VAT. Plans start at €10.80.
More comparisons
- Claude Opus 5.5 vs GPT-6.1 Sol$4.00 / $20.00 vs $2.00 / $10.00 per M tokens
- Claude Opus 5.5 vs GPT-6.1 Sol for coding$4.00 / $20.00 vs $2.00 / $10.00 per M tokens
- Claude Opus 5.5 vs GPT-6.1 Sol for writing$4.00 / $20.00 vs $2.00 / $10.00 per M tokens
- Claude Fable 5.1 vs GPT-6 Astra$10.00 / $50.00 vs $10.00 / $50.00 per M tokens
- Claude Opus 5.5 vs Gemini 3.1 Pro$4.00 / $20.00 vs $2.00 / $12.00 per M tokens
- GPT-6.1 Sol vs Gemini 3.1 Pro$2.00 / $10.00 vs $2.00 / $12.00 per M tokens
Where these figures come from
Prices are each lab's API list price in US dollars per million tokens, as recorded in the model catalog Alevr bills from. Cached input is the rate a prompt-cache hit is billed at. Alevr subscribers do not pay per token: each plan includes a monthly usage budget.
Intelligence and speed are Alevr's 1 to 10 grades. Where Artificial Analysis has measured a model, the grade is computed from its Intelligence Index and median output speed. A model it has not measured yet carries an estimate from the lab's positioning, and the page says so. The benchmark sync last ran on 22 September 2026.
The figures change when labs change their prices. These pages are rebuilt from the same catalog each time Alevr ships, so they match what the app shows.
OpenRouter, a reseller, lists GPT-6 Astra (openai/gpt-6-astra) at $10.00 input and $50.00 output per million tokens. Resale rates can differ from the lab's own.