Model comparison

GPT-5.6 Sol vs o3

GPT-5.6 Sol is the stronger model overall, scoring 65.0 to 47.5 on the Noometry Index. o3 costs 2.3× less per token, which makes it the better buy when GPT-5.6 Sol's lead doesn't matter for your workload.

Last verified . 38 shared benchmarks.

GPT-5.6 Sol OpenAI

65.0

Rank #7 Confirmed

o3 OpenAI

47.5

Rank #61 Confirmed

Summary

  • They share 38 benchmarks with published results for both. GPT-5.6 Sol scores higher in 9 categories and o3 in 1 category; 10 gaps are clear of the uncertainty.
  • The widest gap is in reasoning, where GPT-5.6 Sol leads 74.8 to 32.0.
  • The biggest single-benchmark swing is ARC-AGI-2: 92.5% for GPT-5.6 Sol and 6.5% for o3.
  • o3 is cheaper at $2 / $8 per million input/output tokens, against $4 / $20 for GPT-5.6 Sol.
  • GPT-5.6 Sol accepts more context: 1.05M tokens versus 200K.

Side by side

GPT-5.6 Sol and o3 specifications
GPT-5.6 Solo3
ProviderOpenAIOpenAI
Noometry Index65.047.5
Released2026-07-092025-04-16
WeightsProprietaryProprietary
Context window1.05M200K
Max output128K100K
Input $ / M tokens$4$2
Output $ / M tokens$20$8
Results tracked6563

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Category by category

Coding GPT-5.6 Sol leads

GPT-5.6 Sol: 65.1 (#7), o3: 46.8 (#64)

Coding benchmarks
BenchmarkGPT-5.6 Solo3
GSO76.5%8.8%
WeirdML89.4%52.4%
LMArena Coding14981408
ALE-Bench2,177933.55
SWE-bench Verified—62.3%
DeepSWE72.7%—
FrontierCode47.5%—
SWE-bench Verified (bash only)—58.4%
Aider Polyglot—81.3%
CursorBench41.7%—
LMArena WebDev1618—
FrontierSWE32.2%—
SciCode57.1%—
MirrorCode20%—
CadEval—74%

Agentic & Tool Use GPT-5.6 Sol leads

GPT-5.6 Sol: 50.3 (#7), o3: 34.5 (#44)

Agentic & Tool Use benchmarks
BenchmarkGPT-5.6 Solo3
LMArena Search12571144
APEX-Agents51.4%—
Berkeley Function Calling Leaderboard—63%
OSWorld 2.027.3%—
GDPval—30.8%
τ²-bench Banking46.9%—
DeepResearch Bench—45.2%
OSWorld—23%
PostTrainBench36.2%—
BALROG60%—
GBAEval52.6%—
GDP.pdf30.7%—
METR Time Horizons—65.4%
Vending-Bench 29,619—

Reasoning GPT-5.6 Sol leads

GPT-5.6 Sol: 74.8 (#8), o3: 32.0 (#78)

Reasoning benchmarks
BenchmarkGPT-5.6 Solo3
ARC-AGI-292.5%6.5%
SimpleBench71.7%53.1%
Kagi LLM Benchmark67%67.6%
ARC-AGI-197.5%60.8%
CritPt32.3%1.4%
Chess Puzzles64%38%
EnigmaEval37.1%13.1%
LMArena Hard Prompts14841402
Mystery Game Puzzles58%29%
DTBench96%84.8%
LMCA59.2%39.7%
Epoch Capabilities Index161.66146.86
NYT Connections (extended)93.8%—
EBR-Bench44.8%—
Surface Evolver Bench93.1%—
Bench to the Future 30.14—
ForecastBench—62.5

Math GPT-5.6 Sol leads

GPT-5.6 Sol: 85.6 (#9), o3: 50.2 (#58)

Knowledge GPT-5.6 Sol leads

GPT-5.6 Sol: 64.3 (#18), o3: 54.6 (#52)

Knowledge benchmarks
BenchmarkGPT-5.6 Solo3
GPQA Diamond93.5%81.8%
SimpleQA Verified69.7%49.4%
LMArena Expert15161402
Humanity's Last Exam—20.3%
MMLU-Pro—85.9%
Confabulations—14.4%
Vectara Hallucination Rate12.4%—
GPQA (HELM)—75.3%

Multimodal GPT-5.6 Sol leads

GPT-5.6 Sol: 48.6 (#9), o3: 41.4 (#36)

Multimodal benchmarks
BenchmarkGPT-5.6 Solo3
LMArena Vision12811214
GeoBench—74%
VPCT—52%
Blueprint-Bench 233.6%—
Furniture Assembly56.7%—
LMArena Document1483—

Multilingual GPT-5.6 Sol leads

GPT-5.6 Sol: 55.3 (#32), o3: 51.7 (#105)

Multilingual benchmarks
BenchmarkGPT-5.6 Solo3
LMArena Non-English14521401
LMArena Chinese15271437
LMArena French14771430
LMArena German14761420
LMArena Japanese14711403
LMArena Korean14421370
LMArena Russian14681406
LMArena Spanish14411395

Instruction Following GPT-5.6 Sol leads

GPT-5.6 Sol: 77.7 (#16), o3: 72.8 (#127)

Instruction Following benchmarks
BenchmarkGPT-5.6 Solo3
LMArena Instruction Following14821368
IFEval—86.9%

Long Context o3 leads

GPT-5.6 Sol: 45.4 (#42), o3: 53.3 (#6)

Long Context benchmarks
BenchmarkGPT-5.6 Solo3
LMArena Longer Query14801372
Fiction.LiveBench—88.9%
CL-bench—17.8%

Writing & Preference GPT-5.6 Sol leads

GPT-5.6 Sol: 73.3 (#12), o3: 63.5 (#64)

Writing & Preference benchmarks
BenchmarkGPT-5.6 Solo3
LMArena Text14571410
LMArena Creative Writing14481359
EQ-Bench Creative Writing19721676
LMArena Multi-Turn14601405
Short-Story Creative Writing—83.9%
WildBench—86.1%
EQ-Bench 41250—

Frequently asked questions

Is GPT-5.6 Sol better than o3?

GPT-5.6 Sol is the stronger model overall, scoring 65.0 to 47.5 on the Noometry Index. o3 costs 2.3× less per token, which makes it the better buy when GPT-5.6 Sol's lead doesn't matter for your workload.

Which is cheaper, GPT-5.6 Sol or o3?

o3 is cheaper. It lists at $2 per million input tokens and $8 per million output tokens; GPT-5.6 Sol lists at $4 and $20.

Is GPT-5.6 Sol or o3 better for coding?

GPT-5.6 Sol scores higher on coding benchmarks: 65.1 versus 46.8 in the Noometry coding category.

Which has the bigger context window?

GPT-5.6 Sol does, with 1.05M tokens against 200K.

How many benchmarks do GPT-5.6 Sol and o3 share?

38 benchmarks have published results for both models. GPT-5.6 Sol has 65 scored results on Noometry and o3 has 63.

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