Model comparison

GPT-5 vs gpt-oss-120b

GPT-5 is the stronger model overall, scoring 50.9 to 36.3 on the Noometry Index. gpt-oss-120b costs 49× less per token, which makes it the better buy when GPT-5's lead doesn't matter for your workload.

Last verified . 45 shared benchmarks.

GPT-5 OpenAI

50.9

Rank #45 Confirmed

gpt-oss-120b OpenAI

36.3

Rank #217 Confirmed

Summary

  • They share 45 benchmarks with published results for both. GPT-5 scores higher in 9 categories and gpt-oss-120b in 0 categories; 9 gaps are clear of the uncertainty.
  • The widest gap is in long context, where GPT-5 leads 69.5 to 31.4.
  • The biggest single-benchmark swing is Fiction.LiveBench: 97.2% for GPT-5 and 44.4% for gpt-oss-120b.
  • gpt-oss-120b is cheaper at $0.037 / $0.17 per million input/output tokens, against $1.25 / $10 for GPT-5.
  • GPT-5 accepts more context: 400K tokens versus 131K.
  • gpt-oss-120b has downloadable open weights; the other is API-only.

Side by side

GPT-5 and gpt-oss-120b specifications
GPT-5gpt-oss-120b
ProviderOpenAIOpenAI
Noometry Index50.936.3
Released2025-08-072025-08-05
WeightsProprietaryOpen
Context window400K131K
Max output128K41K
Input $ / M tokens$1.25$0.037
Output $ / M tokens$10$0.17
Results tracked6948

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Category by category

Coding GPT-5 leads

GPT-5: 50.3 (#47), gpt-oss-120b: 33.5 (#256)

Coding benchmarks
BenchmarkGPT-5gpt-oss-120b
SWE-bench Verified (bash only)65%26%
Aider Polyglot88%41.8%
SciCode42.9%36%
WeirdML60.7%48.2%
LMArena Coding14361380
ALE-Bench1,162575.62
AlgoTune1.671.41
SWE-bench Verified73.6%—
LMArena WebDev1418—
GSO6.9%—

Agentic & Tool Use GPT-5 leads

GPT-5: 33.1 (#56), gpt-oss-120b: 12.2 (#153)

Agentic & Tool Use benchmarks
BenchmarkGPT-5gpt-oss-120b
Terminal-Bench49.6%18.7%
METR Time Horizons69.6%56.6%
APEX-Agents—4.4%
GDPval34.8%—
Remote Labor Index1.7%—
DeepResearch Bench49.6%—
BALROG32.8%—
LMArena Search1133—
Vending-Bench 2—-21.53

Reasoning GPT-5 leads

GPT-5: 38.3 (#64), gpt-oss-120b: 20.0 (#245)

Reasoning benchmarks
BenchmarkGPT-5gpt-oss-120b
SimpleBench56.7%22.1%
Kagi LLM Benchmark72.7%58.6%
CritPt12.6%1.1%
Chess Puzzles37%20%
LMArena Hard Prompts14161364
Mystery Game Puzzles23%2%
DTBench90.7%76.3%
LMCA40%22.1%
Epoch Capabilities Index150139.93
ARC-AGI-29.9%—
ARC-AGI-165.7%—
EnigmaEval10.5%—
EBR-Bench12.7%—
Surface Evolver Bench—25%
ForecastBench61.4—

Math GPT-5 leads

GPT-5: 55.0 (#44), gpt-oss-120b: 52.5 (#50)

Math benchmarks
BenchmarkGPT-5gpt-oss-120b
OTIS Mock AIME 2024-202591.4%88.9%
Omni-MATH64.7%68.8%
LMArena Math14071389
FrontierMath (Tiers 1-3)55.4%—
FrontierMath Tier 422%—
ProofBench18%—
MATH Level 598.1%—
FrontierMath (Feb 2025 set)32.4%—
FrontierMath Tier 4 (v1)12.5%—

Knowledge GPT-5 leads

GPT-5: 56.6 (#43), gpt-oss-120b: 42.4 (#96)

Knowledge benchmarks
BenchmarkGPT-5gpt-oss-120b
GPQA Diamond86.2%75.8%
MMLU-Pro86.3%79.5%
Confabulations10.3%15.7%
Vectara Hallucination Rate14.7%14.2%
GPQA (HELM)79.2%68.4%
LMArena Expert14191356
Humanity's Last Exam25.3%—
SimpleQA Verified50.1%—

Multimodal Not comparable

GPT-5: 46.8 (#13), gpt-oss-120b: —

Multimodal benchmarks
BenchmarkGPT-5gpt-oss-120b
LMArena Vision1232—
GeoBench81%—
VPCT66%—

Multilingual GPT-5 leads

GPT-5: 51.4 (#110), gpt-oss-120b: 48.0 (#147)

Multilingual benchmarks
BenchmarkGPT-5gpt-oss-120b
LMArena Non-English13971351
LMArena Chinese14221385
LMArena French14101369
LMArena German14161353
LMArena Japanese14091331
LMArena Korean13601282
LMArena Russian14061343
LMArena Spanish13991389

Instruction Following GPT-5 leads

GPT-5: 73.8 (#113), gpt-oss-120b: 69.3 (#173)

Instruction Following benchmarks
BenchmarkGPT-5gpt-oss-120b
IFEval87.5%83.6%
LMArena Instruction Following13881318

Long Context GPT-5 leads

GPT-5: 69.5 (#2), gpt-oss-120b: 31.4 (#278)

Long Context benchmarks
BenchmarkGPT-5gpt-oss-120b
Fiction.LiveBench97.2%44.4%
LMArena Longer Query13991319

Writing & Preference GPT-5 leads

GPT-5: 63.4 (#65), gpt-oss-120b: 46.5 (#217)

Writing & Preference benchmarks
BenchmarkGPT-5gpt-oss-120b
LMArena Text14061365
LMArena Creative Writing13651275
Short-Story Creative Writing86%77.1%
EQ-Bench Creative Writing1627961
WildBench85.7%84.5%
LMArena Multi-Turn14261340

Frequently asked questions

Is GPT-5 better than gpt-oss-120b?

GPT-5 is the stronger model overall, scoring 50.9 to 36.3 on the Noometry Index. gpt-oss-120b costs 49× less per token, which makes it the better buy when GPT-5's lead doesn't matter for your workload.

Which is cheaper, GPT-5 or gpt-oss-120b?

gpt-oss-120b is cheaper. It lists at $0.037 per million input tokens and $0.17 per million output tokens; GPT-5 lists at $1.25 and $10.

Is GPT-5 or gpt-oss-120b better for coding?

GPT-5 scores higher on coding benchmarks: 50.3 versus 33.5 in the Noometry coding category.

Which has the bigger context window?

GPT-5 does, with 400K tokens against 131K.

How many benchmarks do GPT-5 and gpt-oss-120b share?

45 benchmarks have published results for both models. GPT-5 has 69 scored results on Noometry and gpt-oss-120b has 48.

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