Anthropic

Claude Opus 5

Access via Nexus

Claude Opus 5 is a proprietary model from Anthropic, released Jul 24, 2026. It ranks #4 of 351 on the LMArena text leaderboard with a rating of 1508. It costs $5 per million input tokens and $25 per million output tokens, with a 1M-token context window.

LMArena text1508
Rank#4/351
95% interval1504–1513
Votes34.5K
Developer
Anthropic
Released
Jul 24, 2026
Context window
1M
Price in / out, per 1M tokens
$5 / $25
Weights
Proprietary
Inputs
Text, Images, Files
Reasoning
Yes
Tool use
Yes

Benchmarks

BenchmarkScore barAccuracyRankCost / test
Terminal-Bench 4.0Coding53.53%9 / 55$18.60
SWE-benchCoding97.00%1 / 85$1.29
Vibe Code BenchCoding88.40%9 / 115$33.88
LiveCodeBenchCoding89.03%4 / 143$5 / $25
Tax Agent BenchFinance45.55%4 / 76$5.14
Legal Research BenchLaw55.29%2 / 85$6.76
MedCodeMedicine63.57%1 / 107$5 / $25
GPQA DiamondReasoning93.43%8 / 138$5 / $25
MMLU-ProReasoning91.59%2 / 138$5 / $25
MMMUReasoning89.88%2 / 93$5 / $25
Terminal-Bench ScienceReasoning27.14%9 / 42$32.54

Vals AI, as of Oct 24, 2026.

LMArena, by category

LeaderboardRatingRankVotes
TextLMArena15084 / 35134.5K
CodingLMArena15334 / 34618.2K
MathLMArena15332 / 3391.7K
Creative writingLMArena14955 / 3497.9K
Instruction followingLMArena15185 / 35112K
Hard promptsLMArena15274 / 35122.2K
Multi-turnLMArena150010 / 3495.2K
Long queriesLMArena15174 / 33016.2K
ExpertLMArena15531 / 3057.9K
Legal and governmentIndustries15291 / 3253K
Medicine and healthcareIndustries15263 / 3252.6K
Business and financeIndustries15012 / 3446.4K
ChineseLanguages15734 / 3282.7K
SpanishLanguages15221 / 2491K
GermanLanguages15301 / 261584
FrenchLanguages15184 / 2522.3K
JapaneseLanguages15213 / 236609
WebDevLMArena16919 / 12419K
VisionLMArena13203 / 14617.7K

LMArena, CC BY 4.0, as of Oct 22, 2026. Where a model is rated at several effort levels, its best is shown (Claude Opus 5 (Max), Claude Opus 5 (High)).

Compare Claude Opus 5

Anthropic

An AI safety and research company that builds the Claude family of models, known for coding, long context and careful behaviour. Founded 2021, based in San Francisco. anthropic.com

Questions

Who makes Claude Opus 5?

Claude Opus 5 is made by Anthropic, founded 2021 and based in San Francisco.

How much does Claude Opus 5 cost?

$5 per million input tokens and $25 per million output tokens, at its provider’s list price.

What is Claude Opus 5’s context window?

1M tokens (1,000,000).

How does Claude Opus 5 rank?

#4 of 351 on LMArena’s text leaderboard, rated 1508 (95% interval 1504–1513) from 34,526 votes, as of Oct 22, 2026.

Is Claude Opus 5 open source?

No. Claude Opus 5 is proprietary and served through its provider’s API.

Sources

Every number on this page comes from these sources; models without a published number show none. Download the data. Cite as “Nexus Explorer, nexus.inc/models”.