Claude Opus 5.5 (Xhigh, Default Fallback)

By Anthropic · released 2026-09-22 (4 weeks) · snapshot 2026-10-24

On the Pareto frontierOn frontier at launch dayproprietary

Intelligence index: 56.00
Cost to run the AA index: $4057
Price per 1M tokens (in / out): $4.00 / $20.0
End-to-end time: 112.6s

Better than…

Is Claude Opus 5.5 (Xhigh, Default Fallback) on the Pareto frontier, and what beats it?

On the Pareto frontier

Yes. Nothing live under $10,000 is both smarter and cheaper to run.

The daily check URL below returns 409 the day that changes.

Open in the picker Daily check URL: 200 on the frontier, 409 once beaten

Matchup

Compare head to head

Suggested: what beats it, its effort levels, and frontier models near its price.

Compare Claude Opus 5.5 (Xhigh, Default Fallback) with measured models

Release

What the Claude Opus 5.5 release did to the frontier on 2026-09-22

4 of 5 effort levels reached the frontier at launch (Claude Opus 5.5 (Medium, Default Fallback), Claude Opus 5.5 (High, Default Fallback), Claude Opus 5.5 (Xhigh, Default Fallback), Claude Opus 5.5 (Max, Default Fallback)). Impact 4.17, #9 of 46 releases this past year.

Release page: launch-day frontier and every effort level

Deciding

Should you use Claude Opus 5.5 (Xhigh, Default Fallback)?

Yes, for the money: nothing live under $10,000 is both smarter and cheaper to run, so it sits on the value frontier.

What is better and cheaper than Claude Opus 5.5 (Xhigh, Default Fallback)?

Nothing: no live model under $10,000 is both smarter and cheaper.

How much does Claude Opus 5.5 (Xhigh, Default Fallback) cost?

$4.00/$20 in/out per 1M tokens, and $4057 to run the full Artificial Analysis Intelligence Index, the honest all-in number for reasoning models.

Is Claude Opus 5.5 (Xhigh, Default Fallback) on the Pareto frontier?

Yes: Claude Opus 5.5 (Xhigh, Default Fallback) is on the intelligence-vs-cost Pareto frontier.

Frontier membership by axis pair

Other axis pairs where Claude Opus 5.5 (Xhigh, Default Fallback) is Pareto-optimal.

Y axis	X axis	On the frontier
AA intelligence index	AA total cost to run (USD)
AA intelligence index	End-to-end total seconds
AA intelligence index	Output speed tokens/sec

Agents: Accept: text/markdown or ?format=md returns this page as Markdown. JSON: /api/v1/models/claude-opus-5-5-xhigh · Markdown: /api/v1/models/claude-opus-5-5-xhigh?format=md · llms.txt · agent skill

Is Claude Opus 5.5 (Xhigh, Default Fallback) on the Pareto frontier, and what beats it?

On the Pareto frontier