Skip to content
Model Index
  • Overview
  • Models
  • Compare
  • Benchmarks
  • Finder
LabsMethodology
  1. Models
  2. Anthropic

Claude Opus 5.5

Anthropic · released Sep 22, 2026

FlagshipAPI onlyOn the efficient frontier

The model Anthropic tells most developers to start with: built for long autonomous coding sessions and document-heavy professional work. It lands close to — and on many benchmarks above — the pricier Fable 5.1 at 40% of the per-token price.

Best for: Agentic coding · Knowledge work · Computer use

Announcement
Intelligence Index
57.6
#1 of 38 · at Max effort
Price per 1M tokens
$4 in $20 out
Blended $8 at 3:1
Context window
1M
Up to 128K output
Output speed
95 tokens/s
$5.98 measured cost per task

Capability profile

One 0–100 score per area, placing this model between the weakest and strongest tracked model across that area's benchmarks.

  • Overall96 · #1 of 38

    Based on 3 of 3 benchmarks

  • Coding97 · #1 of 39

    Based on 5 of 5 benchmarks

  • Agents & knowledge work91 · #2 of 40

    Based on 6 of 6 benchmarks

  • Reasoning & science100 · #1 of 39

    Based on 2 of 2 benchmarks

  • Knowledge & reliability97 · #1 of 39

    Based on 2 of 2 benchmarks

  • Vision100 · #1 of 31

    Based on 1 of 2 benchmarks

Reasoning effort trade-off

The same model at each effort setting. Lower settings give up a few points for a fraction of the cost and wait.

SettingIntelligence IndexCost / taskFirst answer
Max
57.6
$5.9812 min
xHigh
56.0
$3.462.2 min
HighSweet spot
53.6
$1.8238s
Medium
51.2
$1.3423s
Low
42.3
$0.558.7s

Measured by Artificial Analysis. First answer is the median wait until the first answer token, including thinking time. “Sweet spot” is the cheapest setting that keeps at least 90% of the top score for no more than 60% of its cost.

Benchmark results

All third-party results on record. Rank is among the tracked models that have been tested on that benchmark.

Overall

  • Artificial Analysis Intelligence Index57.6

    #1 of 38· Max effort· Artificial Analysis

  • Vals Index67.0%

    #3 of 26· Max effort· $32.1 per test· Vals AI

  • Arena · Text1504 ±9

    #2 of 33· High effort· 4,552 votes· Arena

Coding

  • Terminal-Bench 4.059.6%

    #2 of 38· Max effort· Artificial Analysis

  • SciCode66.9%

    #1 of 38· Max effort· Artificial Analysis

  • Arena · WebDev1814 ±16

    #1 of 34· Max effort· 2,229 votes· Arena

  • Vibe Code Bench90.3%

    #4 of 26· Max effort· Vals AI

  • Code Migration68.9%

    #3 of 26· Max effort· Vals AI

Agents & knowledge work

  • GDPval-AA68.3

    #1 of 39· Max effort· Artificial Analysis

  • Arena · Agent+13.8 ±2.2

    #2 of 29· High effort· Arena

  • Finance Agent v258.6%

    #5 of 26· Max effort· Vals AI

  • Excel Modeling Benchmark75.9%

    #2 of 26· Max effort· Vals AI

  • Legal Research Bench50.5%

    #4 of 26· Max effort· Vals AI

  • Tax Agent Bench70.5%

    #6 of 26· Max effort· Vals AI

Reasoning & science

  • Humanity's Last Exam61.4%

    #1 of 39· Max effort· Artificial Analysis

  • CritPt31.7%

    #1 of 39· Max effort· Artificial Analysis

  • ARC-AGI-2saturating93.3%

    #3 of 16· High effort· $0.41 per task· ARC Prize

  • ARC-AGI-3Not tested
  • GPQA DiamondsaturatingNot tested

Knowledge & reliability

  • AA-Omniscience46

    #1 of 39· Max effort· Artificial Analysis

  • AA-LCR84.7%

    #5 of 39· Max effort· Artificial Analysis

Vision

  • MMMU-Pro87.7%

    #1 of 27· Max effort· Artificial Analysis

  • Arena · VisionNot tested

Reported by Anthropic

Numbers the lab published at launch, run on its own harness and settings. Useful context, but not independently verified and never used in the rankings on this site.

  • Terminal-Bench 4.0 · xHigh effort66.4%
  • SWE-bench Pro · Max effort89.9%
  • OSWorld 2.1 · partial score81.8%
  • CursorBench 4.0 · run by Cursor57.8%
  • Humanity's Last Exam · no tools64.4%

Specifications

Lab
Anthropic
Released
Sep 22, 2026
Availability
Generally available
Context window
1,000,000 tokens
Max output
128,000 tokens
Accepts
Text, Images, PDFs
Knowledge cutoff
Jun 2026
Weights
Closed
Reasoning control
Always on · effort low to max
API model ID
claude-opus-5-5

Pricing

Input / 1M tokens
$4
Cached input / 1M
$0.20
Output / 1M tokens
$20
Blended (3:1)
$8
Measured cost / task
$5.98

Full 1M context at standard rates. Batch API is half price; a fast mode costs double.

Worth knowing

  • Safeguards hand some cybersecurity and life-science requests to an older Opus model. Independent evaluators score what the product returns, so their results include those fallbacks.

Official sources

  • Announcement
  • Documentation
  • System card

Closest alternatives

The models nearest to this one on overall score.

  • Gemini 4 Argon
    Intelligence Index
    52.6
    Price / 1M
    $4
    Compare the two
  • Claude Fable 5.1
    Intelligence Index
    53.4
    Price / 1M
    $20
    Compare the two
  • Claude Sonnet 5.5
    Intelligence Index
    56.0
    Price / 1M
    $4
    Compare the two
  • GPT-6 Astra
    Intelligence Index
    52.7
    Price / 1M
    $20
    Compare the two

23 benchmarks tracked. See methodology and sources.

Model Index

An independent snapshot of frontier SI models and how they perform on third-party benchmarks.

Data as of Oct 8, 2026

Explore

  • All models
  • Compare
  • Benchmarks
  • Model finder
  • Labs
  • Methodology & sources

Sources

Benchmark results come from Artificial Analysis, Arena, Vals AI and ARC Prize. Specifications and prices come from each lab's own documentation.

Not affiliated with any lab or evaluator. Names and logos are trademarks of their respective owners and are used only to identify them. Scores change often — check the linked source before making a decision that depends on one.

  • Overview
  • Models
  • Compare
  • Benchmarks
  • Finder
  • Overview
  • Models
  • Compare
  • Benchmarks
  • Finder
  • Overview
  • Models
  • Compare
  • Benchmarks
  • Finder