Model comparison

gpt-oss-120b vs Grok 4.3

Grok 4.3 is the stronger model overall, scoring 43.8 to 36.3 on the Noometry Index. gpt-oss-120b costs 22× less per token, which makes it the better buy when Grok 4.3's lead doesn't matter for your workload.

Last verified . 28 shared benchmarks.

gpt-oss-120b OpenAI

36.3

Rank #217 Confirmed

Grok 4.3 xAI

43.8

Rank #86 Confirmed

Summary

  • They share 28 benchmarks with published results for both. gpt-oss-120b scores higher in 1 category and Grok 4.3 in 8 categories; 9 gaps are clear of the uncertainty.
  • The widest gap is in reasoning, where Grok 4.3 leads 35.9 to 20.0.
  • The biggest single-benchmark swing is LMCA: 22.1% for gpt-oss-120b and 38.3% for Grok 4.3.
  • gpt-oss-120b is cheaper at $0.037 / $0.17 per million input/output tokens, against $1.25 / $2.50 for Grok 4.3.
  • Grok 4.3 accepts more context: 1M tokens versus 131K.
  • gpt-oss-120b has downloadable open weights; the other is API-only.

Side by side

gpt-oss-120b and Grok 4.3 specifications
gpt-oss-120bGrok 4.3
ProviderOpenAIxAI
Noometry Index36.343.8
Released2025-08-052026-04-17
WeightsOpenProprietary
Context window131K1M
Max output41K30K
Input $ / M tokens$0.037$1.25
Output $ / M tokens$0.17$2.50
Results tracked4840

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Category by category

Coding Grok 4.3 leads

gpt-oss-120b: 33.5 (#256), Grok 4.3: 41.6 (#121)

Coding benchmarks
Benchmarkgpt-oss-120bGrok 4.3
SciCode36%47.3%
WeirdML48.2%49.9%
LMArena Coding13801415
ALE-Bench575.62944.17
SWE-bench Verified (bash only)26%—
Aider Polyglot41.8%—
LMArena WebDev—1357
AlgoTune1.41—

Agentic & Tool Use Grok 4.3 leads

gpt-oss-120b: 12.2 (#153), Grok 4.3: 27.7 (#99)

Agentic & Tool Use benchmarks
Benchmarkgpt-oss-120bGrok 4.3
Vending-Bench 2-21.5335.26
Terminal-Bench18.7%—
APEX-Agents4.4%—
GDP.pdf—8%
LMArena Search—1165
METR Time Horizons56.6%—

Reasoning Grok 4.3 leads

gpt-oss-120b: 20.0 (#245), Grok 4.3: 35.9 (#68)

Reasoning benchmarks
Benchmarkgpt-oss-120bGrok 4.3
CritPt1.1%8%
Chess Puzzles20%25%
LMArena Hard Prompts13641396
DTBench76.3%90.7%
LMCA22.1%38.3%
Epoch Capabilities Index139.93149.16
SimpleBench22.1%—
Kagi LLM Benchmark58.6%—
NYT Connections (extended)—55.2%
Mystery Game Puzzles2%—
Surface Evolver Bench25%—
ForecastBench—60.3

Math gpt-oss-120b leads

gpt-oss-120b: 52.5 (#50), Grok 4.3: 46.0 (#74)

Math benchmarks
Benchmarkgpt-oss-120bGrok 4.3
OTIS Mock AIME 2024-202588.9%93.3%
LMArena Math13891388
FrontierMath (Tiers 1-3)—42.8%
FrontierMath Tier 4—14.6%
ProofBench—11%
Omni-MATH68.8%—

Knowledge Grok 4.3 leads

gpt-oss-120b: 42.4 (#96), Grok 4.3: 52.5 (#62)

Knowledge benchmarks
Benchmarkgpt-oss-120bGrok 4.3
GPQA Diamond75.8%88.8%
LMArena Expert13561385
SimpleQA Verified—33.2%
MMLU-Pro79.5%—
Confabulations15.7%—
Vectara Hallucination Rate14.2%—
GPQA (HELM)68.4%—

Multimodal Not comparable

gpt-oss-120b: —, Grok 4.3: 31.6 (#104)

Multimodal benchmarks
Benchmarkgpt-oss-120bGrok 4.3
LMArena Vision—1229
Blueprint-Bench 2—0%

Multilingual Grok 4.3 leads

gpt-oss-120b: 48.0 (#147), Grok 4.3: 50.5 (#120)

Multilingual benchmarks
Benchmarkgpt-oss-120bGrok 4.3
LMArena Non-English13511385
LMArena Chinese13851422
LMArena French13691412
LMArena German13531395
LMArena Japanese13311379
LMArena Korean12821356
LMArena Russian13431399
LMArena Spanish13891398

Instruction Following Grok 4.3 leads

gpt-oss-120b: 69.3 (#173), Grok 4.3: 72.1 (#140)

Instruction Following benchmarks
Benchmarkgpt-oss-120bGrok 4.3
LMArena Instruction Following13181366
IFEval83.6%—

Long Context Grok 4.3 leads

gpt-oss-120b: 31.4 (#278), Grok 4.3: 42.5 (#123)

Long Context benchmarks
Benchmarkgpt-oss-120bGrok 4.3
LMArena Longer Query13191393
Fiction.LiveBench44.4%—

Writing & Preference Grok 4.3 leads

gpt-oss-120b: 46.5 (#217), Grok 4.3: 58.5 (#118)

Writing & Preference benchmarks
Benchmarkgpt-oss-120bGrok 4.3
LMArena Text13651397
LMArena Creative Writing12751380
LMArena Multi-Turn13401406
Short-Story Creative Writing77.1%—
EQ-Bench Creative Writing961—
WildBench84.5%—
EQ-Bench 4—1075

Frequently asked questions

Is gpt-oss-120b better than Grok 4.3?

Grok 4.3 is the stronger model overall, scoring 43.8 to 36.3 on the Noometry Index. gpt-oss-120b costs 22× less per token, which makes it the better buy when Grok 4.3's lead doesn't matter for your workload.

Which is cheaper, gpt-oss-120b or Grok 4.3?

gpt-oss-120b is cheaper. It lists at $0.037 per million input tokens and $0.17 per million output tokens; Grok 4.3 lists at $1.25 and $2.50.

Is gpt-oss-120b or Grok 4.3 better for coding?

Grok 4.3 scores higher on coding benchmarks: 41.6 versus 33.5 in the Noometry coding category.

Which has the bigger context window?

Grok 4.3 does, with 1M tokens against 131K.

How many benchmarks do gpt-oss-120b and Grok 4.3 share?

28 benchmarks have published results for both models. gpt-oss-120b has 48 scored results on Noometry and Grok 4.3 has 40.

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