Noometry

Model comparison

Claude Opus 4.5 vs GPT-6 Astra

GPT-6 Astra is the stronger model overall, scoring 70.8 to 50.5 on the Noometry Index. Claude Opus 4.5 costs 2.0× less per token, which makes it the better buy when GPT-6 Astra's lead doesn't matter for your workload.

Last verified . 44 shared benchmarks.

Claude Opus 4.5 Anthropic

50.5

Rank #47 Confirmed

GPT-6 Astra OpenAI

70.8

Rank #1 Confirmed

Summary

  • They share 44 benchmarks with published results for both. Claude Opus 4.5 scores higher in 3 categories and GPT-6 Astra in 7 categories; 9 gaps are clear of the uncertainty.
  • The widest gap is in math, where GPT-6 Astra leads 93.5 to 38.6.
  • The biggest single-benchmark swing is FrontierMath Tier 4: 4.9% for Claude Opus 4.5 and 97.6% for GPT-6 Astra.
  • Claude Opus 4.5 is cheaper at $5 / $25 per million input/output tokens, against $10 / $50 for GPT-6 Astra.
  • GPT-6 Astra accepts more context: 1.05M tokens versus 200K.

Side by side

Claude Opus 4.5GPT-6 Astra
ProviderAnthropicOpenAI
Noometry Index50.570.8
Released2025-11-012026-09-03
WeightsProprietaryProprietary
Context window200K1.05M
Max output64K128K
Input $ / M tokens$5$10
Output $ / M tokens$25$50
Results tracked6956

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Category by category

Coding GPT-6 Astra leads

Claude Opus 4.5: 54.8 (#27), GPT-6 Astra: 73.7 (#2)

BenchmarkClaude Opus 4.5GPT-6 Astra
LMArena WebDev14941786
GSO26.5%79.4%
WeirdML63.7%93.6%
LMArena Coding15041487
ALE-Bench1,0252,951
SWE-bench Verified76.7%—
DeepSWE—74.1%
FrontierCode—53.3%
SWE-bench Verified (bash only)76.8%—
SWE-bench Multilingual70.7%—
FrontierSWE—65.5%
SciCode—56.5%
MirrorCode—46.7%
AlgoTune1.77—

Agentic & Tool Use GPT-6 Astra leads

Claude Opus 4.5: 47.3 (#12), GPT-6 Astra: 52.9 (#3)

BenchmarkClaude Opus 4.5GPT-6 Astra
Remote Labor Index3.8%20.8%
BALROG43.5%68.3%
Vending-Bench 24,96715,515
Terminal-Bench63.1%—
APEX-Agents—64.7%
Berkeley Function Calling Leaderboard77.5%—
GDPval45.5%—
τ²-bench Airline84%—
τ²-bench Banking24.7%—
τ²-bench Retail79.6%—
τ²-bench Telecom92.3%—
Cybench82%—
DeepResearch Bench54.8%—
OSWorld66.3%—
GDP.pdf—34.2%
LMArena Search1180—
METR Time Horizons75%—

Reasoning GPT-6 Astra leads

Claude Opus 4.5: 42.6 (#51), GPT-6 Astra: 85.1 (#1)

BenchmarkClaude Opus 4.5GPT-6 Astra
ARC-AGI-237.6%95%
NYT Connections (extended)52.5%98.1%
ARC-AGI-180%98.5%
Chess Puzzles12%72%
EBR-Bench14.3%76.2%
LMArena Hard Prompts14761462
Mystery Game Puzzles22%84%
DTBench89.9%97.3%
LMCA44.5%64.4%
Epoch Capabilities Index150.09166.45
SimpleBench62%—
Kagi LLM Benchmark80.2%—
CritPt—31.7%
EnigmaEval11.9%—
Bench to the Future 3—0.14
ForecastBench60.7—

Math GPT-6 Astra leads

Claude Opus 4.5: 38.6 (#132), GPT-6 Astra: 93.5 (#2)

BenchmarkClaude Opus 4.5GPT-6 Astra
FrontierMath (Tiers 1-3)34.4%93.7%
FrontierMath Tier 44.9%97.6%
OTIS Mock AIME 2024-202586.1%100%
ProofBench36%99%
LMArena Math14631465
FrontierMath (Feb 2025 set)20.7%—
FrontierMath Erdős—2.9%
FrontierMath Tier 4 (v1)4.2%—

Knowledge GPT-6 Astra leads

Claude Opus 4.5: 56.5 (#44), GPT-6 Astra: 75.3 (#1)

BenchmarkClaude Opus 4.5GPT-6 Astra
GPQA Diamond86%95.8%
Humanity's Last Exam25.2%54.8%
SimpleQA Verified45.7%75.6%
Vectara Hallucination Rate10.9%8.7%
LMArena Expert14871483

Multimodal GPT-6 Astra leads

Claude Opus 4.5: 31.4 (#107), GPT-6 Astra: 55.0 (#3)

BenchmarkClaude Opus 4.5GPT-6 Astra
Furniture Assembly28.3%80%
LMArena Document14621468
LMArena Vision—1281
GeoBench75%—
VPCT40%—
Blueprint-Bench 2—49.7%

Multilingual Too close to call

Claude Opus 4.5: 54.3 (#47), GPT-6 Astra: 53.7 (#61)

BenchmarkClaude Opus 4.5GPT-6 Astra
LMArena Non-English14381430
LMArena Chinese14701484
LMArena French14711456
LMArena German14491440
LMArena Japanese14161379
LMArena Korean14241426
LMArena Russian14471436
LMArena Spanish14581407

Instruction Following Claude Opus 4.5 leads

Claude Opus 4.5: 77.5 (#19), GPT-6 Astra: 76.3 (#44)

BenchmarkClaude Opus 4.5GPT-6 Astra
LMArena Instruction Following14781450

Long Context Claude Opus 4.5 leads

Claude Opus 4.5: 46.5 (#22), GPT-6 Astra: 44.5 (#62)

BenchmarkClaude Opus 4.5GPT-6 Astra
LMArena Longer Query14801456
CL-bench21.1%—

Writing & Preference GPT-6 Astra leads

Claude Opus 4.5: 68.1 (#28), GPT-6 Astra: 75.3 (#7)

BenchmarkClaude Opus 4.5GPT-6 Astra
LMArena Text14511441
LMArena Creative Writing14451418
EQ-Bench Creative Writing16872173
LMArena Multi-Turn14661448

Frequently asked questions

Is Claude Opus 4.5 better than GPT-6 Astra?

GPT-6 Astra is the stronger model overall, scoring 70.8 to 50.5 on the Noometry Index. Claude Opus 4.5 costs 2.0× less per token, which makes it the better buy when GPT-6 Astra's lead doesn't matter for your workload.

Which is cheaper, Claude Opus 4.5 or GPT-6 Astra?

Claude Opus 4.5 is cheaper. It lists at $5 per million input tokens and $25 per million output tokens; GPT-6 Astra lists at $10 and $50.

Is Claude Opus 4.5 or GPT-6 Astra better for coding?

GPT-6 Astra scores higher on coding benchmarks: 73.7 versus 54.8 in the Noometry coding category.

Which has the bigger context window?

GPT-6 Astra does, with 1.05M tokens against 200K.

How many benchmarks do Claude Opus 4.5 and GPT-6 Astra share?

44 benchmarks have published results for both models. Claude Opus 4.5 has 69 scored results on Noometry and GPT-6 Astra has 56.

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