Model decision surface
Compare AI models
Start with Claude Opus 5.5 and Gemini 3.1 Pro Preview, 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 Gemini 3.1 Pro Preview
Live dataset updated 9/22/2026, 10:37:09 PM UTC
Open 1200×630 evidence receipt| Field | Claude Opus 5.5 Anthropic | Gemini 3.1 Pro Preview |
|---|---|---|
| ModelCap position | #1 | #17 |
| Index score | 98.6 | 81.5 |
| Evidence | Measured2 public benchmark observations across 2 boards | Measured4 public benchmark observations across 4 boards |
| Input / 1M | $4.00 | $2.00 |
| Output / 1M | $20.00 | $12.00 |
| Pricing status | fresh | fresh |
| Context | 1M | 1M |
| Providers | 5 | 2 |
| Weight access | API only | API only |
Decision facts
- Claude Opus 5.5 is #1; Gemini 3.1 Pro Preview is #17 on the same current language board.
- Index scores are 98.6 for Claude Opus 5.5 and 81.5 for Gemini 3.1 Pro Preview. 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 $12.00 for Gemini 3.1 Pro Preview. 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 $10.00 for Gemini 3.1 Pro Preview. Gemini 3.1 Pro Preview costs 44.4% 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 Gemini 3.1 Pro Preview.
- ModelCap currently lists 5 providers for Claude Opus 5.5 and 2 for Gemini 3.1 Pro Preview.
These are separate published fields, not a synthetic winner. ModelCap does not collapse price, access, context, and capability evidence into a hidden recommendation score.
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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.