Claude Opus 5.5
Anthropic · released 22 Sep 2026 · proprietary API
- Newest release (3-way tie)
Long-running agentic coding and knowledge work; supersedes Claude Opus 5. Thinking is always on and cannot be disabled.
Context window
1M
1,000,000 tokens
Input price
$4
per 1M tokens
Output price
$20
per 1M tokens
Blended
$8
3:1 in:out mix
Weights
Proprietary
API only
Released
22 Sep 2026
Anthropic
Long-context / tier pricing — Cache reads $0.20/1M, 0.05x base input; fast mode (research preview) bills at $8 in / $40 out. Uses the post-4.7 tokenizer, about 30% more tokens for the same text. Listed prices are the base rate for prompts up to ~200K tokens.
Where it ranks
Of 40 models tracked.
Cost to run
#32(tied)
of 40
Input price
#32(tied)
of 40
Context window
#9(tied)
of 40
Compare with
The nearest models by blended cost to run.
Put it to work
Specs from BitByteCore's hand-verified Frontier Ledger (v2026-09-23), this row verified 22 Sep 2026 against Anthropic's official pricing ↗. Model pricing moves fast, so confirm with Anthropic before you rely on a figure.