Model comparison

Claude Opus 5 vs GPT-5.1

Claude Opus 5 is the stronger model overall, scoring 67.8 to 49.0 on the Noometry Index. GPT-5.1 costs 2.9× less per token, which makes it the better buy when Claude Opus 5's lead doesn't matter for your workload.

Last verified . 36 shared benchmarks.

Claude Opus 5 Anthropic

67.8

Rank #4 Confirmed

GPT-5.1 OpenAI

49.0

Rank #53 Confirmed

Summary

  • They share 36 benchmarks with published results for both. Claude Opus 5 scores higher in 8 categories and GPT-5.1 in 2 categories; 10 gaps are clear of the uncertainty.
  • The widest gap is in reasoning, where Claude Opus 5 leads 77.2 to 39.8.
  • The biggest single-benchmark swing is ARC-AGI-2: 90.4% for Claude Opus 5 and 17.6% for GPT-5.1.
  • GPT-5.1 is cheaper at $1.25 / $10 per million input/output tokens, against $5 / $25 for Claude Opus 5.
  • Claude Opus 5 accepts more context: 1M tokens versus 400K.

Side by side

Claude Opus 5 and GPT-5.1 specifications
Claude Opus 5GPT-5.1
ProviderAnthropicOpenAI
Noometry Index67.849.0
Released2026-07-242025-11-13
WeightsProprietaryProprietary
Context window1M400K
Max output128K128K
Input $ / M tokens$5$1.25
Output $ / M tokens$25$10
Results tracked5763

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Category by category

Coding Claude Opus 5 leads

Claude Opus 5: 67.5 (#5), GPT-5.1: 46.4 (#66)

Coding benchmarks
BenchmarkClaude Opus 5GPT-5.1
LMArena WebDev16911395
SciCode56.4%43.3%
WeirdML91.8%60.8%
LMArena Coding15341454
ALE-Bench2,1651,192
SWE-bench Verified—68%
DeepSWE73.6%—
FrontierCode53.4%—
SWE-bench Verified (bash only)—66%
CursorBench46.6%—
FrontierSWE52%—
GSO—13.7%
LiveBench Coding—72.5%

Agentic & Tool Use Claude Opus 5 leads

Claude Opus 5: 55.6 (#1), GPT-5.1: 32.7 (#60)

Agentic & Tool Use benchmarks
BenchmarkClaude Opus 5GPT-5.1
Vending-Bench 211,1821,473
Terminal-Bench—47.6%
APEX-Agents65.8%—
OSWorld 2.031.4%—
τ²-bench Banking48.7%—
DeepResearch Bench—42.8%
PostTrainBench35%—
BALROG63.4%—
GBAEval79.6%—
GDP.pdf24%—
LMArena Search—1199

Reasoning Claude Opus 5 leads

Claude Opus 5: 77.2 (#4), GPT-5.1: 39.8 (#58)

Reasoning benchmarks
BenchmarkClaude Opus 5GPT-5.1
ARC-AGI-290.4%17.6%
SimpleBench80.6%53.2%
ARC-AGI-197.5%72.8%
CritPt29.1%4.9%
Chess Puzzles42%32%
LMArena Hard Prompts15261457
Mystery Game Puzzles59%19%
DTBench97.9%90.1%
LMCA64.5%43.9%
Epoch Capabilities Index162.78149.64
NYT Connections (extended)94.3%—
EnigmaEval—11.2%
EBR-Bench45.7%—
LiveBench Reasoning—95.8%
LiveBench Data Analysis—72.1%
Bench to the Future 30.12—
ForecastBench—58.1
LiveBench—78.8%

Math Claude Opus 5 leads

Claude Opus 5: 86.2 (#8), GPT-5.1: 52.2 (#51)

Math benchmarks
BenchmarkClaude Opus 5GPT-5.1
OTIS Mock AIME 2024-202598.9%88.6%
LMArena Math15311447
FrontierMath (Tiers 1-3)85.6%—
FrontierMath Tier 473.2%—
ProofBench99%—
Omni-MATH—46.4%
LiveBench Math—94.5%
FrontierMath (Feb 2025 set)—31%
FrontierMath Tier 4 (v1)—12.5%

Knowledge Claude Opus 5 leads

Claude Opus 5: 66.8 (#9), GPT-5.1: 50.6 (#71)

Knowledge benchmarks
BenchmarkClaude Opus 5GPT-5.1
GPQA Diamond93.9%87.6%
SimpleQA Verified59.9%48%
LMArena Expert15571470
Humanity's Last Exam—23.7%
MMLU-Pro—57.9%
Vectara Hallucination Rate—10.9%
GPQA (HELM)—44.2%

Multimodal Claude Opus 5 leads

Claude Opus 5: 50.8 (#8), GPT-5.1: 44.8 (#19)

Multimodal benchmarks
BenchmarkClaude Opus 5GPT-5.1
LMArena Vision13191250
LMArena Document15161403
VPCT—58.7%
Blueprint-Bench 230.4%—
Furniture Assembly60.8%—

Multilingual Claude Opus 5 leads

Claude Opus 5: 58.8 (#4), GPT-5.1: 53.8 (#56)

Multilingual benchmarks
BenchmarkClaude Opus 5GPT-5.1
LMArena Non-English15011431
LMArena Chinese15741495
LMArena French15191450
LMArena German15241438
LMArena Japanese15161453
LMArena Korean15211401
LMArena Russian15071435
LMArena Spanish15191433

Instruction Following GPT-5.1 leads

Claude Opus 5: 79.2 (#7), GPT-5.1: 83.9 (#1)

Instruction Following benchmarks
BenchmarkClaude Opus 5GPT-5.1
LMArena Instruction Following15171443
LiveBench Instruction Following—93.3%
IFEval—93.5%

Long Context GPT-5.1 leads

Claude Opus 5: 46.5 (#21), GPT-5.1: 47.6 (#14)

Long Context benchmarks
BenchmarkClaude Opus 5GPT-5.1
LMArena Longer Query15151447
CL-bench—23.7%
CL-bench Life—17.3%

Writing & Preference Claude Opus 5 leads

Claude Opus 5: 79.2 (#1), GPT-5.1: 64.5 (#55)

Writing & Preference benchmarks
BenchmarkClaude Opus 5GPT-5.1
LMArena Text15071443
LMArena Creative Writing14911427
LMArena Multi-Turn14991450
EQ-Bench Creative Writing2133—
WildBench—86.3%
EQ-Bench 41385—
LiveBench Language—80.2%

Frequently asked questions

Is Claude Opus 5 better than GPT-5.1?

Claude Opus 5 is the stronger model overall, scoring 67.8 to 49.0 on the Noometry Index. GPT-5.1 costs 2.9× less per token, which makes it the better buy when Claude Opus 5's lead doesn't matter for your workload.

Which is cheaper, Claude Opus 5 or GPT-5.1?

GPT-5.1 is cheaper. It lists at $1.25 per million input tokens and $10 per million output tokens; Claude Opus 5 lists at $5 and $25.

Is Claude Opus 5 or GPT-5.1 better for coding?

Claude Opus 5 scores higher on coding benchmarks: 67.5 versus 46.4 in the Noometry coding category.

Which has the bigger context window?

Claude Opus 5 does, with 1M tokens against 400K.

How many benchmarks do Claude Opus 5 and GPT-5.1 share?

36 benchmarks have published results for both models. Claude Opus 5 has 57 scored results on Noometry and GPT-5.1 has 63.

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