Model comparison

GPT-5.5 vs GPT-5 Nano

GPT-5.5 is the stronger model overall, scoring 63.4 to 33.4 on the Noometry Index. GPT-5 Nano costs 82× less per token, which makes it the better buy when GPT-5.5's lead doesn't matter for your workload.

Last verified . 38 shared benchmarks.

GPT-5.5 OpenAI

63.4

Rank #8 Confirmed

GPT-5 Nano OpenAI

33.4

Rank #234 Confirmed

Summary

  • They share 38 benchmarks with published results for both. GPT-5.5 scores higher in 10 categories and GPT-5 Nano in 0 categories; 10 gaps are clear of the uncertainty.
  • The widest gap is in reasoning, where GPT-5.5 leads 72.7 to 16.4.
  • The biggest single-benchmark swing is ARC-AGI-2: 85% for GPT-5.5 and 2.6% for GPT-5 Nano.
  • GPT-5 Nano is cheaper at $0.05 / $0.40 per million input/output tokens, against $5 / $30 for GPT-5.5.
  • GPT-5.5 accepts more context: 1.05M tokens versus 400K.

Side by side

GPT-5.5 and GPT-5 Nano specifications
GPT-5.5GPT-5 Nano
ProviderOpenAIOpenAI
Noometry Index63.433.4
Released2026-04-232025-08-07
WeightsProprietaryProprietary
Context window1.05M400K
Max output128K128K
Input $ / M tokens$5$0.05
Output $ / M tokens$30$0.40
Results tracked7148

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Category by category

Coding GPT-5.5 leads

GPT-5.5: 58.3 (#13), GPT-5 Nano: 33.3 (#248)

Coding benchmarks
BenchmarkGPT-5.5GPT-5 Nano
WeirdML84.9%38.1%
LMArena Coding14941351
ALE-Bench1,943718.67
SWE-bench Verified80.6%—
DeepSWE67%—
FrontierCode43%—
SWE-bench Verified (bash only)—34.8%
LMArena WebDev1512—
SciCode56.1%—
GSO40.2%—
MirrorCode10%—

Agentic & Tool Use GPT-5.5 leads

GPT-5.5: 50.7 (#6), GPT-5 Nano: 25.6 (#99)

Agentic & Tool Use benchmarks
BenchmarkGPT-5.5GPT-5 Nano
Terminal-Bench84.7%21.8%
APEX-Agents55.1%—
Berkeley Function Calling Leaderboard—51.5%
OSWorld 2.013%—
Remote Labor Index6.3%—
τ²-bench Banking44.6%—
DeepResearch Bench54%—
PostTrainBench27.2%—
ExploitBench47.4%—
GBAEval53.2%—
GDP.pdf26%—
LMArena Search1242—
Vending-Bench 27,524—

Reasoning GPT-5.5 leads

GPT-5.5: 72.7 (#8), GPT-5 Nano: 16.4 (#291)

Reasoning benchmarks
BenchmarkGPT-5.5GPT-5 Nano
ARC-AGI-285%2.6%
Kagi LLM Benchmark88.8%62.2%
ARC-AGI-195%20.7%
Chess Puzzles54%27%
LMArena Hard Prompts14891329
Mystery Game Puzzles56%9%
DTBench96%62.7%
LMCA54.3%7.9%
Epoch Capabilities Index159.25139.39
ForecastBench60.659.1
SimpleBench69%—
NYT Connections (extended)96.2%—
CritPt27.1%—
EBR-Bench34.3%—
Surface Evolver Bench88.1%—
Bench to the Future 30.14—

Math GPT-5.5 leads

GPT-5.5: 81.5 (#9), GPT-5 Nano: 29.1 (#221)

Knowledge GPT-5.5 leads

GPT-5.5: 64.4 (#14), GPT-5 Nano: 35.8 (#166)

Knowledge benchmarks
BenchmarkGPT-5.5GPT-5 Nano
GPQA Diamond94%69.4%
SimpleQA Verified63%11.7%
Vectara Hallucination Rate9.3%10.5%
LMArena Expert15081321
MMLU-Pro—77.8%
GPQA (HELM)—67.9%

Multimodal GPT-5.5 leads

GPT-5.5: 47.1 (#11), GPT-5 Nano: 30.7 (#102)

Multimodal benchmarks
BenchmarkGPT-5.5GPT-5 Nano
LMArena Vision12971159
VPCT—37.2%
Blueprint-Bench 236.2%—
Furniture Assembly44.2%—
LMArena Document1486—

Multilingual GPT-5.5 leads

GPT-5.5: 56.5 (#19), GPT-5 Nano: 45.5 (#167)

Multilingual benchmarks
BenchmarkGPT-5.5GPT-5 Nano
LMArena Non-English14671313
LMArena Chinese15351355
LMArena German14781329
LMArena Korean14611269
LMArena Russian14731296
LMArena Spanish14691360
LMArena French1486—
LMArena Japanese1498—

Instruction Following GPT-5.5 leads

GPT-5.5: 77.7 (#18), GPT-5 Nano: 75.2 (#72)

Instruction Following benchmarks
BenchmarkGPT-5.5GPT-5 Nano
LMArena Instruction Following14791306
IFEval—93.2%

Long Context GPT-5.5 leads

GPT-5.5: 48.3 (#12), GPT-5 Nano: 31.3 (#275)

Long Context benchmarks
BenchmarkGPT-5.5GPT-5 Nano
LMArena Longer Query14841313
Fiction.LiveBench—44.4%
CL-bench Life22.2%—

Writing & Preference GPT-5.5 leads

GPT-5.5: 72.8 (#13), GPT-5 Nano: 39.4 (#244)

Writing & Preference benchmarks
BenchmarkGPT-5.5GPT-5 Nano
LMArena Text14711320
LMArena Creative Writing14551250
EQ-Bench Creative Writing1844705
LMArena Multi-Turn14771311
WildBench—80.6%
EQ-Bench 41315—

Frequently asked questions

Is GPT-5.5 better than GPT-5 Nano?

GPT-5.5 is the stronger model overall, scoring 63.4 to 33.4 on the Noometry Index. GPT-5 Nano costs 82× less per token, which makes it the better buy when GPT-5.5's lead doesn't matter for your workload.

Which is cheaper, GPT-5.5 or GPT-5 Nano?

GPT-5 Nano is cheaper. It lists at $0.05 per million input tokens and $0.40 per million output tokens; GPT-5.5 lists at $5 and $30.

Is GPT-5.5 or GPT-5 Nano better for coding?

GPT-5.5 scores higher on coding benchmarks: 58.3 versus 33.3 in the Noometry coding category.

Which has the bigger context window?

GPT-5.5 does, with 1.05M tokens against 400K.

How many benchmarks do GPT-5.5 and GPT-5 Nano share?

38 benchmarks have published results for both models. GPT-5.5 has 71 scored results on Noometry and GPT-5 Nano has 48.

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