Model summary
Speed
Claude Opus 5.5 (Adaptive Reasoning, Max Effort, Default Fallback) is amongst the leading models in intelligence, but somewhat expensive when comparing to other models of similar price. The model supports text and image input, outputs text, and has a 1M tokens context window.
Claude Opus 5.5 (Adaptive Reasoning, Max Effort, Default Fallback) scores 58 on the Artificial Analysis Intelligence Index, placing it well above average among comparable models (median: 25). When evaluating the Intelligence Index, it generated 260M tokens, which is very verbose in comparison to the median of 92M.
Pricing for Claude Opus 5.5 (Adaptive Reasoning, Max Effort, Default Fallback) is $4.00 per 1M input tokens (somewhat expensive, median: $2.00) and $20.00 per 1M output tokens (somewhat expensive, median: $10.00). In total, it cost $8708.20 to evaluate Claude Opus 5.5 (Adaptive Reasoning, Max Effort, Default Fallback) on the Intelligence Index.
| Reasoning | Yes This page shows the reasoning version of this model. A non-reasoning variant may also exist. |
|---|---|
| Input modality | Supports: text and image |
| Output modality | Supports: text |
| Context window | 1M ~1500 A4 pages of size 12 Arial font |
Metrics are compared against models of the same class:
- Non-reasoning models → compared only with other non-reasoning models
- Reasoning models → compared across both reasoning and non-reasoning
- Open weights models → compared only with other open weights models of the same size class:
- Tiny: ≤4B parameters
- Small: 4B–40B parameters
- Medium: 40B–150B parameters
- Large: >150B parameters
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Proprietary models → compared across proprietary and open weights models of the same price range, using a blended 3:1 input/output price ratio:
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<$0.15 per 1M tokens
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$0.15–$1 per 1M tokens
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$1 per 1M tokens Highlights
Speed
IntelligenceUpdated #
Artificial Analysis Intelligence Index
Artificial Analysis Intelligence Index by Open Weights / Proprietary
Measures the performance of models on specific capabilities and industries
Artificial Analysis Finance & Accounting Index
Intelligence Evaluations
[AA-Briefcase v1.1](https://artificialanalysis.ai/evaluations/aa-briefcase)Updated
Agentic knowledge work, (Elo-500)/2000
[GDPval-AA v2.1](https://artificialanalysis.ai/evaluations/gdpval-aa)Updated
Agentic real-world work tasks, (Elo-500)/2000
[AutomationBench-AA](https://artificialanalysis.ai/evaluations/automationbench-aa)Updated
Agentic SaaS workflows
Agentic coding & terminal use
Coding
Reasoning & knowledge
GDP.pdfNew Professional document reasoning, All-pass
Physics reasoning
Knowledge
1 - hallucination rate
Long context reasoning
Legal agentic work, criterion pass rate
Agentic business operations
Quantitative analysis on spreadsheets & documents
Agentic tool use
Kubernetes incident root-cause analysis
Visual reasoning
MLCR-AANew Medical long context reasoning
AA-Briefcase v1.1Updated
AA-Briefcase Elo
AA-Omniscience
AA-Omniscience Index
Intelligence Index Comparisons #
Intelligence Index vs. Cost per Intelligence Index Task
Token Use #
Output Tokens per Intelligence Index Task
Cost #
Cost per Intelligence Index Task
Cost to Run Artificial Analysis Intelligence Index
Pricing: Cache Hit, Input, and Output
Context Window #
Context Window
Frequently Asked Questions #
Common questions about Claude Opus 5.5 (Adaptive Reasoning, Max Effort, Default Fallback)
Claude Opus 5.5 (Adaptive Reasoning, Max Effort, Default Fallback) was released on September 22, 2026.
Claude Opus 5.5 (Adaptive Reasoning, Max Effort, Default Fallback) was created by Anthropic.
Claude Opus 5.5 (Adaptive Reasoning, Max Effort, Default Fallback) scores 58 on the Artificial Analysis Intelligence Index, placing it well above average among other reasoning models in a similar price tier (median: 25).
Claude Opus 5.5 (Adaptive Reasoning, Max Effort, Default Fallback) costs $4.00 per 1M input tokens (somewhat higher than average, median: $2.00) and $20.00 per 1M output tokens (somewhat higher than average, median: $10.00), based on Anthropic's API.
Claude Opus 5.5 (Adaptive Reasoning, Max Effort, Default Fallback) costs $4.00 per 1M input tokens and $20.00 per 1M output tokens (based on Anthropic's API). For a blended rate (7:2:1 cache hit/input/output ratio), this is $2.94 per 1M tokens. Pricing may vary by provider. Compare provider pricing
When evaluated on the Intelligence Index, Claude Opus 5.5 (Adaptive Reasoning, Max Effort, Default Fallback) generated 260M output tokens, which is at the higher end compared to other reasoning models in a similar price tier (median: 92M).
Yes, Claude Opus 5.5 (Adaptive Reasoning, Max Effort, Default Fallback) is a reasoning model. It uses extended thinking or chain-of-thought reasoning to work through complex problems before providing an answer.
Claude Opus 5.5 (Adaptive Reasoning, Max Effort, Default Fallback) supports text and image input.
Claude Opus 5.5 (Adaptive Reasoning, Max Effort, Default Fallback) supports text output.
Yes, Claude Opus 5.5 (Adaptive Reasoning, Max Effort, Default Fallback) supports image input and can analyze, describe, and answer questions about images.
Yes, Claude Opus 5.5 (Adaptive Reasoning, Max Effort, Default Fallback) is multimodal. It can process text and image input and generate text output.
Claude Opus 5.5 (Adaptive Reasoning, Max Effort, Default Fallback) has a context window of 1.0M tokens. This determines how much text and conversation history the model can process in a single request.
No, Claude Opus 5.5 (Adaptive Reasoning, Max Effort, Default Fallback) is proprietary. The model weights are not publicly available.
Claude Opus 5.5 (Adaptive Reasoning, Max Effort, Default Fallback) is a proprietary model and Anthropic has not disclosed the model size or parameter count.
Claude Opus 5.5 (Adaptive Reasoning, Max Effort, Default Fallback) achieves a score of 58 on the Artificial Analysis Intelligence Index. This composite benchmark evaluates models across reasoning, knowledge, mathematics, and coding.
Yes, Claude Opus 5.5 (Adaptive Reasoning, Max Effort, Default Fallback) is available via API through 1 provider. Compare API providers
Claude Opus 5.5 (Adaptive Reasoning, Max Effort, Default Fallback) is available through 1 API provider. Compare providers