Model comparison

Claude Opus 5.5 vs GPT-5.6 Sol

Claude Opus 5.5 is the stronger model overall, scoring 68.6 to 65.0 on the Noometry Index.

Last verified . 44 shared benchmarks.

Claude Opus 5.5 Anthropic

68.6

Rank #3 Confirmed

GPT-5.6 Sol OpenAI

65.0

Rank #7 Confirmed

Summary

  • They share 44 benchmarks with published results for both. Claude Opus 5.5 scores higher in 9 categories and GPT-5.6 Sol in 1 category; 10 gaps are clear of the uncertainty.
  • The widest gap is in multimodal, where Claude Opus 5.5 leads 57.8 to 48.6.
  • The biggest single-benchmark swing is MirrorCode: 77.4% for Claude Opus 5.5 and 20% for GPT-5.6 Sol.
  • Both cost about the same: $4 input and $20 output per million tokens.
  • GPT-5.6 Sol accepts more context: 1.05M tokens versus 1M.

Side by side

Claude Opus 5.5 and GPT-5.6 Sol specifications
Claude Opus 5.5GPT-5.6 Sol
ProviderAnthropicOpenAI
Noometry Index68.665.0
Released2026-09-222026-07-09
WeightsProprietaryProprietary
Context window1M1.05M
Max output128K128K
Input $ / M tokens$4$4
Output $ / M tokens$20$20
Results tracked4465

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Category by category

Coding Claude Opus 5.5 leads

Claude Opus 5.5: 71.9 (#3), GPT-5.6 Sol: 65.1 (#7)

Coding benchmarks
BenchmarkClaude Opus 5.5GPT-5.6 Sol
FrontierCode54.6%47.5%
CursorBench57.8%41.7%
LMArena WebDev18131618
FrontierSWE62.3%32.2%
SciCode66.9%57.1%
LMArena Coding15471498
MirrorCode77.4%20%
ALE-Bench2,1472,177
DeepSWE—72.7%
GSO—76.5%
WeirdML—89.4%

Agentic & Tool Use GPT-5.6 Sol leads

Claude Opus 5.5: 45.3 (#15), GPT-5.6 Sol: 50.3 (#7)

Agentic & Tool Use benchmarks
BenchmarkClaude Opus 5.5GPT-5.6 Sol
APEX-Agents73.5%51.4%
GDP.pdf30.6%30.7%
Vending-Bench 29,2359,619
OSWorld 2.0—27.3%
τ²-bench Banking—46.9%
PostTrainBench—36.2%
BALROG—60%
GBAEval—52.6%
LMArena Search—1257

Reasoning Claude Opus 5.5 leads

Claude Opus 5.5: 80.2 (#3), GPT-5.6 Sol: 74.8 (#8)

Reasoning benchmarks
BenchmarkClaude Opus 5.5GPT-5.6 Sol
ARC-AGI-293.3%92.5%
NYT Connections (extended)88.5%93.8%
ARC-AGI-198.5%97.5%
CritPt31.7%32.3%
EBR-Bench71.4%44.8%
LMArena Hard Prompts15351484
Mystery Game Puzzles71%58%
DTBench98.9%96%
LMCA68.2%59.2%
Epoch Capabilities Index167.33161.66
SimpleBench—71.7%
Kagi LLM Benchmark—67%
Chess Puzzles—64%
EnigmaEval—37.1%
Surface Evolver Bench—93.1%
Bench to the Future 3—0.14

Math Claude Opus 5.5 leads

Claude Opus 5.5: 91.8 (#3), GPT-5.6 Sol: 85.6 (#9)

Math benchmarks
BenchmarkClaude Opus 5.5GPT-5.6 Sol
FrontierMath (Tiers 1-3)91.2%89.1%
FrontierMath Tier 495%82.9%
OTIS Mock AIME 2024-2025100%100%
ProofBench100%83%
LMArena Math15061474
FrontierMath Erdős2.9%0%

Knowledge Claude Opus 5.5 leads

Claude Opus 5.5: 66.4 (#10), GPT-5.6 Sol: 64.3 (#18)

Knowledge benchmarks
BenchmarkClaude Opus 5.5GPT-5.6 Sol
GPQA Diamond90.6%93.5%
SimpleQA Verified72.2%69.7%
LMArena Expert15471516
Vectara Hallucination Rate—12.4%

Multimodal Claude Opus 5.5 leads

Claude Opus 5.5: 57.8 (#1), GPT-5.6 Sol: 48.6 (#9)

Multimodal benchmarks
BenchmarkClaude Opus 5.5GPT-5.6 Sol
LMArena Vision13211281
Blueprint-Bench 251.2%33.6%
Furniture Assembly83.3%56.7%
LMArena Document—1483

Multilingual Claude Opus 5.5 leads

Claude Opus 5.5: 59.1 (#2), GPT-5.6 Sol: 55.3 (#32)

Multilingual benchmarks
BenchmarkClaude Opus 5.5GPT-5.6 Sol
LMArena Non-English15071452
LMArena Chinese15881527
LMArena French15141477
LMArena Russian15201468
LMArena Spanish15071441
LMArena German—1476
LMArena Japanese—1471
LMArena Korean—1442

Instruction Following Claude Opus 5.5 leads

Claude Opus 5.5: 80.0 (#3), GPT-5.6 Sol: 77.7 (#16)

Instruction Following benchmarks
BenchmarkClaude Opus 5.5GPT-5.6 Sol
LMArena Instruction Following15371482

Long Context Claude Opus 5.5 leads

Claude Opus 5.5: 47.1 (#19), GPT-5.6 Sol: 45.4 (#42)

Long Context benchmarks
BenchmarkClaude Opus 5.5GPT-5.6 Sol
LMArena Longer Query15321480

Writing & Preference Claude Opus 5.5 leads

Claude Opus 5.5: 78.2 (#3), GPT-5.6 Sol: 73.3 (#12)

Writing & Preference benchmarks
BenchmarkClaude Opus 5.5GPT-5.6 Sol
LMArena Text15151457
LMArena Creative Writing15331448
EQ-Bench Creative Writing20501972
LMArena Multi-Turn14991460
EQ-Bench 4—1250

Frequently asked questions

Is Claude Opus 5.5 better than GPT-5.6 Sol?

Claude Opus 5.5 is the stronger model overall, scoring 68.6 to 65.0 on the Noometry Index.

Which is cheaper, Claude Opus 5.5 or GPT-5.6 Sol?

GPT-5.6 Sol is cheaper. It lists at $4 per million input tokens and $20 per million output tokens; Claude Opus 5.5 lists at $4 and $20.

Is Claude Opus 5.5 or GPT-5.6 Sol better for coding?

Claude Opus 5.5 scores higher on coding benchmarks: 71.9 versus 65.1 in the Noometry coding category.

Which has the bigger context window?

GPT-5.6 Sol does, with 1.05M tokens against 1M.

How many benchmarks do Claude Opus 5.5 and GPT-5.6 Sol share?

44 benchmarks have published results for both models. Claude Opus 5.5 has 44 scored results on Noometry and GPT-5.6 Sol has 65.

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