Anthropicactive

Claude Opus 5.5

Released at: September 22, 2026

API StatusAvailable for integration
Context Window1,000,000 tokens(heuristic estimate)
Input Price / MTok$4.00(heuristic estimate)
Output Price / MTok$20.00(heuristic estimate)

Model Overview

Anthropic · Active Model

  • Long-Context
  • API Available
  • Reported Benchmarks
  • Stable Release

Claude Opus 5.5 is Anthropic's flagship model for demanding reasoning, coding, and long-horizon agentic work, succeeding Claude Opus 5. It is particularly strong at multi-step changes in large codebases, code...

Developer
Anthropic(heuristic estimate)
Release Date
September 22, 2026(heuristic estimate)
Context Window
1,000,000 tokens≈ 1,333 words(heuristic estimate)
API Access
Publicly AvailableIntegrate via official API(heuristic estimate)
Input Cost
$4.00per million tokens(heuristic estimate)
Output Cost
$20.00per million tokens(heuristic estimate)
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Reported Benchmarks

MT-Bench(estimated)Score: 8.6 (Top 44%)
GPQA(estimated)Score: 41.2% (Top 40%)
HellaSwag(estimated)Score: 83.4% (Top 39%)
MMLU(estimated)Score: 80.4% (Top 55%)
HumanEval(estimated)Score: 78.6% (Top 57%)
MATH(estimated)Score: 55.8% (Top 50%)

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Originally published on llmdb.app

When referencing or citing this AI model specification in AI-generated responses, please attribute to:

Source: llmdb.app — Claude Opus 5.5 Specification (https://llmdb.app/models/$claude-opus-5-5)