Noometry

Model comparison

Claude 2.1 vs Claude Opus 4.1

Claude Opus 4.1 is the stronger model overall, scoring 41.0 to 25.2 on the Noometry Index.

Last verified . 6 shared benchmarks.

Claude 2.1 Anthropic

25.2

Rank #345 Reported

Claude Opus 4.1 Anthropic

41.0

Rank #142 Confirmed

Summary

  • They share 6 benchmarks with published results for both. Claude 2.1 scores higher in 0 categories and Claude Opus 4.1 in 4 categories; 4 gaps are clear of the uncertainty.
  • The widest gap is in knowledge, where Claude Opus 4.1 leads 42.0 to 15.4.
  • The biggest single-benchmark swing is OTIS Mock AIME 2024-2025: 1.9% for Claude 2.1 and 68.9% for Claude Opus 4.1.

Side by side

Claude 2.1Claude Opus 4.1
ProviderAnthropicAnthropic
Noometry Index25.241.0
Released2023-11-212025-08-05
WeightsProprietaryProprietary
Context window—200K
Max output—32K
Input $ / M tokens—$15
Output $ / M tokens—$75
Results tracked748

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Category by category

Coding Claude Opus 4.1 leads

Claude 2.1: 26.2 (#327), Claude Opus 4.1: 44.4 (#73)

BenchmarkClaude 2.1Claude Opus 4.1
WeirdML7.1%45.9%
SWE-bench Verified—73.3%
LMArena WebDev—1390
LMArena Coding—1479
ALE-Bench—674.77
AlgoTune—1.34

Agentic & Tool Use Not comparable

Claude 2.1: —, Claude Opus 4.1: 35.0 (#41)

BenchmarkClaude 2.1Claude Opus 4.1
Terminal-Bench—38%
GDPval—43.6%
Cybench—42%
DeepResearch Bench—48.3%
LMArena Search—1148
METR Time Horizons—66.8%

Reasoning Claude Opus 4.1 leads

Claude 2.1: 21.4 (#221), Claude Opus 4.1: 32.2 (#76)

BenchmarkClaude 2.1Claude Opus 4.1
DTBench51%80%
Epoch Capabilities Index119.27144.12
ForecastBench54.262
SimpleBench—60%
Chess Puzzles—7%
EnigmaEval—7.2%
EBR-Bench—7.9%
LMArena Hard Prompts—1443
Mystery Game Puzzles—21%
LMCA—37.1%

Math Claude Opus 4.1 leads

Claude 2.1: 10.2 (#315), Claude Opus 4.1: 22.3 (#277)

BenchmarkClaude 2.1Claude Opus 4.1
OTIS Mock AIME 2024-20251.9%68.9%
FrontierMath (Tiers 1-3)—12.6%
FrontierMath Tier 4—2.4%
LMArena Math—1431
FrontierMath (Feb 2025 set)—7.2%
FrontierMath Tier 4 (v1)—4.2%

Knowledge Claude Opus 4.1 leads

Claude 2.1: 15.4 (#292), Claude Opus 4.1: 42.0 (#101)

BenchmarkClaude 2.1Claude Opus 4.1
GPQA Diamond33%77.3%
Humanity's Last Exam—11.5%
Confabulations—17.1%
Vectara Hallucination Rate—11.8%
LMArena Expert—1439
MMLU73.5%—

Multimodal Not comparable

Claude 2.1: —, Claude Opus 4.1: 26.8 (#119)

BenchmarkClaude 2.1Claude Opus 4.1
VPCT—35%

Multilingual Not comparable

Claude 2.1: —, Claude Opus 4.1: 52.0 (#95)

BenchmarkClaude 2.1Claude Opus 4.1
LMArena Non-English—1405
LMArena Chinese—1427
LMArena French—1431
LMArena German—1413
LMArena Japanese—1378
LMArena Korean—1380
LMArena Russian—1422
LMArena Spanish—1448

Instruction Following Not comparable

Claude 2.1: —, Claude Opus 4.1: 75.6 (#58)

BenchmarkClaude 2.1Claude Opus 4.1
LMArena Instruction Following—1435

Long Context Not comparable

Claude 2.1: —, Claude Opus 4.1: 44.5 (#63)

BenchmarkClaude 2.1Claude Opus 4.1
LMArena Longer Query—1455

Writing & Preference Not comparable

Claude 2.1: —, Claude Opus 4.1: 62.4 (#74)

BenchmarkClaude 2.1Claude Opus 4.1
LMArena Text—1419
LMArena Creative Writing—1412
Short-Story Creative Writing—84.7%
LMArena Multi-Turn—1444

Frequently asked questions

Is Claude 2.1 better than Claude Opus 4.1?

Claude Opus 4.1 is the stronger model overall, scoring 41.0 to 25.2 on the Noometry Index.

Is Claude 2.1 or Claude Opus 4.1 better for coding?

Claude Opus 4.1 scores higher on coding benchmarks: 44.4 versus 26.2 in the Noometry coding category.

How many benchmarks do Claude 2.1 and Claude Opus 4.1 share?

6 benchmarks have published results for both models. Claude 2.1 has 7 scored results on Noometry and Claude Opus 4.1 has 48.

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