Model decision surface
Compare AI models
Start with Claude Opus 5.5 and DeepSeek V4.1 Flash, or choose any two current ranked language models. Compare capability evidence, price, context, provider availability, and weight access without pretending one field decides every use case.
Current public data
Claude Opus 5.5 vs DeepSeek V4.1 Flash
Live dataset updated 9/22/2026, 10:37:09 PM UTC
Open 1200×630 evidence receipt| Field | Claude Opus 5.5 Anthropic | DeepSeek V4.1 Flash DeepSeek |
|---|---|---|
| ModelCap position | #1 | #19 |
| Index score | 98.6 | 80.5 |
| Evidence | Measured2 public benchmark observations across 2 boards | Measured2 public benchmark observations across 2 boards |
| Input / 1M | $4.00 | $0.15 |
| Output / 1M | $20.00 | $0.60 |
| Pricing status | fresh | fresh |
| Context | 1M | 1M |
| Providers | 5 | 23 |
| Weight access | API only | Open weights |
Decision facts
- Claude Opus 5.5 is #1; DeepSeek V4.1 Flash is #19 on the same current language board.
- Index scores are 98.6 for Claude Opus 5.5 and 80.5 for DeepSeek V4.1 Flash. Their published uncertainty intervals overlap, so the rank difference alone does not establish a reliable capability advantage for your workload.
- Both positions use Measured evidence.
- Listed output price per 1M tokens is $20.00 for Claude Opus 5.5 and $0.60 for DeepSeek V4.1 Flash. For 1,000 requests with 2,000 input and 500 output tokens each (2M input + 0.5M output), the listed-rate estimate is $18.00 for Claude Opus 5.5 versus $0.60 for DeepSeek V4.1 Flash. DeepSeek V4.1 Flash costs 96.7% less in this scenario. This excludes caching, batch discounts, prompt-length tiers, tool charges and retries; verify the selected endpoint before budgeting.
- Published context is 1,000,000 tokens for Claude Opus 5.5 and 1,048,576 for DeepSeek V4.1 Flash.
- Weight access differs: Claude Opus 5.5 is none; DeepSeek V4.1 Flash is open.
- ModelCap currently lists 5 providers for Claude Opus 5.5 and 23 for DeepSeek V4.1 Flash.
These are separate published fields, not a synthetic winner. ModelCap does not collapse price, access, context, and capability evidence into a hidden recommendation score.
Popular comparisons
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Each comparison page is a permanent, shareable URL with the same live figures as this tool: ModelCap Index position, API pricing, context window, provider count, weight access and every shared benchmark board.