Model comparison

gpt-oss-120b vs Mistral Small 3

gpt-oss-120b is the stronger model overall, scoring 36.0 to 30.9 on the Noometry Index.

Last verified . 22 shared benchmarks.

gpt-oss-120b OpenAI

36.0

Rank #210 Confirmed

Mistral Small 3 Mistral AI

30.9

Rank #268 Confirmed

Summary

  • They share 22 benchmarks with published results for both. gpt-oss-120b scores higher in 6 categories and Mistral Small 3 in 2 categories; 8 gaps are clear of the uncertainty.
  • The widest gap is in math, where gpt-oss-120b leads 50.6 to 15.3.
  • The biggest single-benchmark swing is OTIS Mock AIME 2024-2025: 88.9% for gpt-oss-120b and 6.7% for Mistral Small 3.
  • Mistral Small 3 is cheaper at $0.05 / $0.08 per million input/output tokens, against $0.037 / $0.17 for gpt-oss-120b.
  • gpt-oss-120b accepts more context: 131K tokens versus 33K.

Side by side

gpt-oss-120b and Mistral Small 3 specifications
gpt-oss-120bMistral Small 3
ProviderOpenAIMistral AI
Noometry Index36.030.9
Released2025-08-052025-01-30
WeightsOpenOpen
Context window131K33K
Max output41K16K
Input $ / M tokens$0.037$0.05
Output $ / M tokens$0.17$0.08
Results tracked4824

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Category by category

Coding Mistral Small 3 leads

gpt-oss-120b: 33.2 (#251), Mistral Small 3: 36.0 (#203)

Coding benchmarks
Benchmarkgpt-oss-120bMistral Small 3
LMArena Coding13801246
SWE-bench Verified (bash only)26%—
Aider Polyglot41.8%—
SciCode36%—
WeirdML48.2%—
BigCodeBench Instruct—45.3%
BigCodeBench Complete—50.4%
ALE-Bench575.62—
AlgoTune1.41—

Agentic & Tool Use Not comparable

gpt-oss-120b: 12.1 (#145), Mistral Small 3: —

Agentic & Tool Use benchmarks
Benchmarkgpt-oss-120bMistral Small 3
Terminal-Bench18.7%—
APEX-Agents4.4%—
METR Time Horizons56.6%—
Vending-Bench 2-21.53—

Reasoning gpt-oss-120b leads

gpt-oss-120b: 19.5 (#236), Mistral Small 3: 18.2 (#269)

Reasoning benchmarks
Benchmarkgpt-oss-120bMistral Small 3
Chess Puzzles20%0%
LMArena Hard Prompts13641233
Epoch Capabilities Index139.94127.06
SimpleBench22.1%—
Kagi LLM Benchmark58.6%—
CritPt1.1%—
Mystery Game Puzzles2%—
DTBench76.3%—
LMCA22.1%—
Surface Evolver Bench25%—

Math gpt-oss-120b leads

gpt-oss-120b: 50.6 (#43), Mistral Small 3: 15.3 (#290)

Math benchmarks
Benchmarkgpt-oss-120bMistral Small 3
OTIS Mock AIME 2024-202588.9%6.7%
LMArena Math13881240
Omni-MATH68.8%—

Knowledge gpt-oss-120b leads

gpt-oss-120b: 42.3 (#89), Mistral Small 3: 25.0 (#258)

Knowledge benchmarks
Benchmarkgpt-oss-120bMistral Small 3
GPQA Diamond75.8%47.3%
Confabulations15.7%25.2%
LMArena Expert13561202
MMLU-Pro79.5%—
Vectara Hallucination Rate14.2%—
GPQA (HELM)68.4%—

Multilingual gpt-oss-120b leads

gpt-oss-120b: 48.2 (#142), Mistral Small 3: 37.5 (#231)

Multilingual benchmarks
Benchmarkgpt-oss-120bMistral Small 3
LMArena Non-English13501198
LMArena Chinese13841204
LMArena French13701202
LMArena German13551211
LMArena Japanese13321111
LMArena Korean12831188
LMArena Russian13431216
LMArena Spanish1388—

Instruction Following gpt-oss-120b leads

gpt-oss-120b: 69.5 (#168), Mistral Small 3: 63.9 (#224)

Instruction Following benchmarks
Benchmarkgpt-oss-120bMistral Small 3
LMArena Instruction Following13181214
IFEval83.6%—

Long Context Mistral Small 3 leads

gpt-oss-120b: 31.4 (#273), Mistral Small 3: 37.8 (#206)

Long Context benchmarks
Benchmarkgpt-oss-120bMistral Small 3
LMArena Longer Query13191246
Fiction.LiveBench44.4%—

Writing & Preference gpt-oss-120b leads

gpt-oss-120b: 46.7 (#213), Mistral Small 3: 32.4 (#275)

Writing & Preference benchmarks
Benchmarkgpt-oss-120bMistral Small 3
LMArena Text13661234
LMArena Creative Writing12741195
EQ-Bench Creative Writing961707
LMArena Multi-Turn13401217
Short-Story Creative Writing77.1%—
WildBench84.5%—

Frequently asked questions

Is gpt-oss-120b better than Mistral Small 3?

gpt-oss-120b is the stronger model overall, scoring 36.0 to 30.9 on the Noometry Index.

Which is cheaper, gpt-oss-120b or Mistral Small 3?

Mistral Small 3 is cheaper. It lists at $0.05 per million input tokens and $0.08 per million output tokens; gpt-oss-120b lists at $0.037 and $0.17.

Is gpt-oss-120b or Mistral Small 3 better for coding?

Mistral Small 3 scores higher on coding benchmarks: 36.0 versus 33.2 in the Noometry coding category.

Which has the bigger context window?

gpt-oss-120b does, with 131K tokens against 33K.

How many benchmarks do gpt-oss-120b and Mistral Small 3 share?

22 benchmarks have published results for both models. gpt-oss-120b has 48 scored results on Noometry and Mistral Small 3 has 24.

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