Noometry

Model comparison

gpt-oss-20b vs Mistral Small 3

gpt-oss-20b is the stronger model overall, scoring 32.5 to 31.2 on the Noometry Index.

Last verified . 20 shared benchmarks.

gpt-oss-20b OpenAI

32.5

Rank #255 Confirmed

Mistral Small 3 Mistral AI

31.2

Rank #278 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 39.4 to 16.3.
  • 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 Index32.531.2
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: 37.6 (#192), Mistral Small 3: 36.5 (#207)

Benchmarkgpt-oss-20bMistral Small 3
LMArena Coding13061246
SciCode34.4%—
WeirdML40.9%—
BigCodeBench Instruct—45.3%
BigCodeBench Complete—50.4%
ALE-Bench566.05—

Agentic & Tool Use Not comparable

gpt-oss-20b: 9.3 (#154), Mistral Small 3: —

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

Reasoning Too close to call

gpt-oss-20b: 19.3 (#261), Mistral Small 3: 18.9 (#273)

Benchmarkgpt-oss-20bMistral Small 3
Chess Puzzles4%0%
LMArena Hard Prompts12741233
Epoch Capabilities Index137.82127.07
Kagi LLM Benchmark53.2%—
CritPt1.4%—
DTBench68%—
LMCA14.5%—

Math gpt-oss-20b leads

gpt-oss-20b: 39.4 (#103), Mistral Small 3: 16.3 (#295)

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 (#195), Mistral Small 3: 25.1 (#263)

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: 42.2 (#197), Mistral Small 3: 37.3 (#236)

Benchmarkgpt-oss-20bMistral Small 3
LMArena Non-English12681198
LMArena Chinese13141204
LMArena German12551211
LMArena Japanese12441111
LMArena Korean12361188
LMArena Russian12781216
LMArena French—1203
LMArena Spanish1267—

Instruction Following Mistral Small 3 leads

gpt-oss-20b: 61.8 (#240), Mistral Small 3: 63.7 (#229)

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

Long Context Too close to call

gpt-oss-20b: 37.9 (#209), Mistral Small 3: 37.8 (#211)

Benchmarkgpt-oss-20bMistral Small 3
LMArena Longer Query12501246

Writing & Preference gpt-oss-20b leads

gpt-oss-20b: 35.5 (#265), Mistral Small 3: 32.2 (#280)

Benchmarkgpt-oss-20bMistral Small 3
LMArena Text12871234
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 32.5 to 31.2 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: 37.6 versus 36.5 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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