Noometry

Model comparison

Claude Opus 4.5 vs GPT-5.1

Claude Opus 4.5 is the stronger model overall, scoring 50.5 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 4.5's lead doesn't matter for your workload.

Last verified . 47 shared benchmarks.

Claude Opus 4.5 Anthropic

50.5

Rank #47 Confirmed

GPT-5.1 OpenAI

49.0

Rank #53 Confirmed

Summary

  • They share 47 benchmarks with published results for both. Claude Opus 4.5 scores higher in 6 categories and GPT-5.1 in 4 categories; 9 gaps are clear of the uncertainty.
  • The widest gap is in agentic & tool use, where Claude Opus 4.5 leads 47.3 to 32.7.
  • The biggest single-benchmark swing is ARC-AGI-2: 37.6% for Claude Opus 4.5 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 4.5.
  • GPT-5.1 accepts more context: 400K tokens versus 200K.

Side by side

Claude Opus 4.5GPT-5.1
ProviderAnthropicOpenAI
Noometry Index50.549.0
Released2025-11-012025-11-13
WeightsProprietaryProprietary
Context window200K400K
Max output64K128K
Input $ / M tokens$5$1.25
Output $ / M tokens$25$10
Results tracked6963

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Category by category

Coding Claude Opus 4.5 leads

Claude Opus 4.5: 54.8 (#27), GPT-5.1: 46.4 (#66)

BenchmarkClaude Opus 4.5GPT-5.1
SWE-bench Verified76.7%68%
SWE-bench Verified (bash only)76.8%66%
LMArena WebDev14941395
GSO26.5%13.7%
WeirdML63.7%60.8%
LMArena Coding15041454
ALE-Bench1,0251,192
SWE-bench Multilingual70.7%—
SciCode—43.3%
LiveBench Coding—72.5%
AlgoTune1.77—

Agentic & Tool Use Claude Opus 4.5 leads

Claude Opus 4.5: 47.3 (#12), GPT-5.1: 32.7 (#60)

BenchmarkClaude Opus 4.5GPT-5.1
Terminal-Bench63.1%47.6%
DeepResearch Bench54.8%42.8%
LMArena Search11801199
Vending-Bench 24,9671,473
Berkeley Function Calling Leaderboard77.5%—
GDPval45.5%—
Remote Labor Index3.8%—
τ²-bench Airline84%—
τ²-bench Banking24.7%—
τ²-bench Retail79.6%—
τ²-bench Telecom92.3%—
Cybench82%—
OSWorld66.3%—
BALROG43.5%—
METR Time Horizons75%—

Reasoning Claude Opus 4.5 leads

Claude Opus 4.5: 42.6 (#51), GPT-5.1: 39.8 (#58)

BenchmarkClaude Opus 4.5GPT-5.1
ARC-AGI-237.6%17.6%
SimpleBench62%53.2%
ARC-AGI-180%72.8%
Chess Puzzles12%32%
EnigmaEval11.9%11.2%
LMArena Hard Prompts14761457
Mystery Game Puzzles22%19%
DTBench89.9%90.1%
LMCA44.5%43.9%
Epoch Capabilities Index150.09149.64
ForecastBench60.758.1
Kagi LLM Benchmark80.2%—
NYT Connections (extended)52.5%—
CritPt—4.9%
EBR-Bench14.3%—
LiveBench Reasoning—95.8%
LiveBench Data Analysis—72.1%
LiveBench—78.8%

Math GPT-5.1 leads

Claude Opus 4.5: 38.6 (#132), GPT-5.1: 52.2 (#51)

BenchmarkClaude Opus 4.5GPT-5.1
OTIS Mock AIME 2024-202586.1%88.6%
LMArena Math14631447
FrontierMath (Feb 2025 set)20.7%31%
FrontierMath Tier 4 (v1)4.2%12.5%
FrontierMath (Tiers 1-3)34.4%—
FrontierMath Tier 44.9%—
ProofBench36%—
Omni-MATH—46.4%
LiveBench Math—94.5%

Knowledge Claude Opus 4.5 leads

Claude Opus 4.5: 56.5 (#44), GPT-5.1: 50.6 (#71)

BenchmarkClaude Opus 4.5GPT-5.1
GPQA Diamond86%87.6%
Humanity's Last Exam25.2%23.7%
SimpleQA Verified45.7%48%
Vectara Hallucination Rate10.9%10.9%
LMArena Expert14871470
MMLU-Pro—57.9%
GPQA (HELM)—44.2%

Multimodal GPT-5.1 leads

Claude Opus 4.5: 31.4 (#107), GPT-5.1: 44.8 (#19)

BenchmarkClaude Opus 4.5GPT-5.1
VPCT40%58.7%
LMArena Document14621403
LMArena Vision—1250
GeoBench75%—
Furniture Assembly28.3%—

Multilingual Too close to call

Claude Opus 4.5: 54.3 (#47), GPT-5.1: 53.8 (#56)

BenchmarkClaude Opus 4.5GPT-5.1
LMArena Non-English14381431
LMArena Chinese14701495
LMArena French14711450
LMArena German14491438
LMArena Japanese14161453
LMArena Korean14241401
LMArena Russian14471435
LMArena Spanish14581433

Instruction Following GPT-5.1 leads

Claude Opus 4.5: 77.5 (#19), GPT-5.1: 83.9 (#1)

BenchmarkClaude Opus 4.5GPT-5.1
LMArena Instruction Following14781443
LiveBench Instruction Following—93.3%
IFEval—93.5%

Long Context GPT-5.1 leads

Claude Opus 4.5: 46.5 (#22), GPT-5.1: 47.6 (#14)

BenchmarkClaude Opus 4.5GPT-5.1
CL-bench21.1%23.7%
LMArena Longer Query14801447
CL-bench Life—17.3%

Writing & Preference Claude Opus 4.5 leads

Claude Opus 4.5: 68.1 (#28), GPT-5.1: 64.5 (#55)

BenchmarkClaude Opus 4.5GPT-5.1
LMArena Text14511443
LMArena Creative Writing14451427
LMArena Multi-Turn14661450
EQ-Bench Creative Writing1687—
WildBench—86.3%
LiveBench Language—80.2%

Frequently asked questions

Is Claude Opus 4.5 better than GPT-5.1?

Claude Opus 4.5 is the stronger model overall, scoring 50.5 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 4.5's lead doesn't matter for your workload.

Which is cheaper, Claude Opus 4.5 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 4.5 lists at $5 and $25.

Is Claude Opus 4.5 or GPT-5.1 better for coding?

Claude Opus 4.5 scores higher on coding benchmarks: 54.8 versus 46.4 in the Noometry coding category.

Which has the bigger context window?

GPT-5.1 does, with 400K tokens against 200K.

How many benchmarks do Claude Opus 4.5 and GPT-5.1 share?

47 benchmarks have published results for both models. Claude Opus 4.5 has 69 scored results on Noometry and GPT-5.1 has 63.

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