Noometry

Model comparison

gpt-oss-20b vs Mistral Small 3

gpt-oss-20b is the stronger model overall, scoring 32.1 to 30.9 on the Noometry Index.

Last verified . 20 shared benchmarks.

gpt-oss-20b OpenAI

32.1

Rank #249 Confirmed

Mistral Small 3 Mistral AI

30.9

Rank #268 Confirmed

Summary

  • They share 20 benchmarks with published results for both. gpt-oss-20b scores higher in 7 categories and Mistral Small 3 in 1 category; 6 gaps are clear of the uncertainty.
  • The widest gap is in math, where gpt-oss-20b leads 37.6 to 15.3.
  • The biggest single-benchmark swing is OTIS Mock AIME 2024-2025: 65.3% for gpt-oss-20b and 6.7% for Mistral Small 3.
  • gpt-oss-20b is cheaper at $0.018 / $0.09 per million input/output tokens, against $0.05 / $0.08 for Mistral Small 3.
  • gpt-oss-20b accepts more context: 131K tokens versus 33K.

Side by side

gpt-oss-20bMistral Small 3
ProviderOpenAIMistral AI
Noometry Index32.130.9
Released2025-08-052025-01-30
WeightsOpenOpen
Context window131K33K
Max output16K16K
Input $ / M tokens$0.018$0.05
Output $ / M tokens$0.09$0.08
Results tracked3424

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Category by category

Coding gpt-oss-20b leads

gpt-oss-20b: 37.1 (#185), Mistral Small 3: 36.0 (#203)

Benchmarkgpt-oss-20bMistral Small 3
LMArena Coding13071246
SciCode34.4%—
WeirdML40.9%—
BigCodeBench Instruct—45.3%
BigCodeBench Complete—50.4%
ALE-Bench566.05—

Agentic & Tool Use Not comparable

gpt-oss-20b: 9.2 (#146), Mistral Small 3: —

Benchmarkgpt-oss-20bMistral Small 3
Terminal-Bench3.4%—

Reasoning Too close to call

gpt-oss-20b: 18.8 (#251), Mistral Small 3: 18.2 (#269)

Benchmarkgpt-oss-20bMistral Small 3
Chess Puzzles4%0%
LMArena Hard Prompts12741233
Epoch Capabilities Index137.81127.06
Kagi LLM Benchmark53.2%—
CritPt1.4%—
DTBench68%—
LMCA14.5%—

Math gpt-oss-20b leads

gpt-oss-20b: 37.6 (#93), Mistral Small 3: 15.3 (#290)

Benchmarkgpt-oss-20bMistral Small 3
OTIS Mock AIME 2024-202565.3%6.7%
LMArena Math13171240
Omni-MATH56.5%—

Knowledge gpt-oss-20b leads

gpt-oss-20b: 34.6 (#186), Mistral Small 3: 25.0 (#258)

Benchmarkgpt-oss-20bMistral Small 3
GPQA Diamond60.8%47.3%
LMArena Expert12581202
MMLU-Pro74%—
Confabulations—25.2%
GPQA (HELM)59.4%—

Multilingual gpt-oss-20b leads

gpt-oss-20b: 42.4 (#192), Mistral Small 3: 37.5 (#231)

Benchmarkgpt-oss-20bMistral Small 3
LMArena Non-English12691198
LMArena Chinese13111204
LMArena German12491211
LMArena Japanese12451111
LMArena Korean12391188
LMArena Russian12791216
LMArena French—1202
LMArena Spanish1267—

Instruction Following Mistral Small 3 leads

gpt-oss-20b: 62.0 (#235), Mistral Small 3: 63.9 (#224)

Benchmarkgpt-oss-20bMistral Small 3
LMArena Instruction Following12361214
IFEval73.2%—

Long Context Too close to call

gpt-oss-20b: 37.9 (#203), Mistral Small 3: 37.8 (#206)

Benchmarkgpt-oss-20bMistral Small 3
LMArena Longer Query12511246

Writing & Preference gpt-oss-20b leads

gpt-oss-20b: 35.8 (#260), Mistral Small 3: 32.4 (#275)

Benchmarkgpt-oss-20bMistral Small 3
LMArena Text12881234
LMArena Creative Writing12011195
EQ-Bench Creative Writing666707
LMArena Multi-Turn12681217
WildBench73.7%—

Frequently asked questions

Is gpt-oss-20b better than Mistral Small 3?

gpt-oss-20b is the stronger model overall, scoring 32.1 to 30.9 on the Noometry Index.

Which is cheaper, gpt-oss-20b or Mistral Small 3?

gpt-oss-20b is cheaper. It lists at $0.018 per million input tokens and $0.09 per million output tokens; Mistral Small 3 lists at $0.05 and $0.08.

Is gpt-oss-20b or Mistral Small 3 better for coding?

gpt-oss-20b scores higher on coding benchmarks: 37.1 versus 36.0 in the Noometry coding category.

Which has the bigger context window?

gpt-oss-20b does, with 131K tokens against 33K.

How many benchmarks do gpt-oss-20b and Mistral Small 3 share?

20 benchmarks have published results for both models. gpt-oss-20b has 34 scored results on Noometry and Mistral Small 3 has 24.

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