Model comparison

gpt-oss-20b vs Mistral Medium

Mistral Medium is the stronger model overall, scoring 36.3 to 32.5 on the Noometry Index. gpt-oss-20b costs 83× less per token, which makes it the better buy when Mistral Medium's lead doesn't matter for your workload.

Last verified . 25 shared benchmarks.

gpt-oss-20b OpenAI

32.5

Rank #255 Confirmed

Mistral Medium Mistral AI

36.3

Rank #218 Confirmed

Summary

  • They share 25 benchmarks with published results for both. gpt-oss-20b scores higher in 3 categories and Mistral Medium in 6 categories; 9 gaps are clear of the uncertainty.
  • The widest gap is in writing & preference, where Mistral Medium leads 60.0 to 35.5.
  • The biggest single-benchmark swing is OTIS Mock AIME 2024-2025: 65.3% for gpt-oss-20b and 32.2% for Mistral Medium.
  • gpt-oss-20b is cheaper at $0.018 / $0.09 per million input/output tokens, against $1.50 / $7.50 for Mistral Medium.
  • Mistral Medium accepts more context: 262K tokens versus 131K.

Side by side

gpt-oss-20b and Mistral Medium specifications
gpt-oss-20bMistral Medium
ProviderOpenAIMistral AI
Noometry Index32.536.3
Released2025-08-052023-12-11
WeightsOpenOpen
Context window131K262K
Max output16K262K
Input $ / M tokens$0.018$1.50
Output $ / M tokens$0.09$7.50
Results tracked3436

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Category by category

Coding gpt-oss-20b leads

gpt-oss-20b: 37.6 (#192), Mistral Medium: 34.2 (#243)

Coding benchmarks
Benchmarkgpt-oss-20bMistral Medium
SciCode34.4%40.2%
WeirdML40.9%43.7%
LMArena Coding13061434
ALE-Bench566.05763.98
FrontierCode—8%

Agentic & Tool Use Mistral Medium leads

gpt-oss-20b: 9.3 (#154), Mistral Medium: 28.3 (#90)

Agentic & Tool Use benchmarks
Benchmarkgpt-oss-20bMistral Medium
Terminal-Bench3.4%—
Berkeley Function Calling Leaderboard—37.7%

Reasoning Mistral Medium leads

gpt-oss-20b: 19.3 (#261), Mistral Medium: 24.0 (#167)

Reasoning benchmarks
Benchmarkgpt-oss-20bMistral Medium
Kagi LLM Benchmark53.2%50%
CritPt1.4%0%
LMArena Hard Prompts12741426
DTBench68%75.5%
LMCA14.5%26.1%
Chess Puzzles4%—
Surface Evolver Bench—26.9%
Epoch Capabilities Index137.82—

Math gpt-oss-20b leads

gpt-oss-20b: 39.4 (#103), Mistral Medium: 28.1 (#245)

Math benchmarks
Benchmarkgpt-oss-20bMistral Medium
OTIS Mock AIME 2024-202565.3%32.2%
LMArena Math13171408
ProofBench—9%
Omni-MATH56.5%—
MATH Level 5—81.6%
FrontierMath (Feb 2025 set)—0.3%

Knowledge gpt-oss-20b leads

gpt-oss-20b: 34.6 (#195), Mistral Medium: 25.0 (#265)

Knowledge benchmarks
Benchmarkgpt-oss-20bMistral Medium
GPQA Diamond60.8%59.5%
LMArena Expert12581408
Humanity's Last Exam—4.5%
MMLU-Pro74%—
Vectara Hallucination Rate—22.7%
GPQA (HELM)59.4%—

Multimodal Not comparable

gpt-oss-20b: —, Mistral Medium: 35.3 (#88)

Multimodal benchmarks
Benchmarkgpt-oss-20bMistral Medium
LMArena Vision—1172

Multilingual Mistral Medium leads

gpt-oss-20b: 42.2 (#197), Mistral Medium: 52.1 (#91)

Multilingual benchmarks
Benchmarkgpt-oss-20bMistral Medium
LMArena Non-English12681408
LMArena Chinese13141447
LMArena German12551432
LMArena Japanese12441378
LMArena Korean12361380
LMArena Russian12781411
LMArena Spanish12671433
LMArena French—1459

Instruction Following Mistral Medium leads

gpt-oss-20b: 61.8 (#240), Mistral Medium: 73.7 (#116)

Instruction Following benchmarks
Benchmarkgpt-oss-20bMistral Medium
LMArena Instruction Following12361398
IFEval73.2%—

Long Context Mistral Medium leads

gpt-oss-20b: 37.9 (#209), Mistral Medium: 42.9 (#114)

Long Context benchmarks
Benchmarkgpt-oss-20bMistral Medium
LMArena Longer Query12501406

Writing & Preference Mistral Medium leads

gpt-oss-20b: 35.5 (#265), Mistral Medium: 60.0 (#103)

Writing & Preference benchmarks
Benchmarkgpt-oss-20bMistral Medium
LMArena Text12871424
LMArena Creative Writing12011391
LMArena Multi-Turn12681418
Short-Story Creative Writing—77.3%
EQ-Bench Creative Writing666—
WildBench73.7%—

Frequently asked questions

Is gpt-oss-20b better than Mistral Medium?

Mistral Medium is the stronger model overall, scoring 36.3 to 32.5 on the Noometry Index. gpt-oss-20b costs 83× less per token, which makes it the better buy when Mistral Medium's lead doesn't matter for your workload.

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

gpt-oss-20b is cheaper. It lists at $0.018 per million input tokens and $0.09 per million output tokens; Mistral Medium lists at $1.50 and $7.50.

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

gpt-oss-20b scores higher on coding benchmarks: 37.6 versus 34.2 in the Noometry coding category.

Which has the bigger context window?

Mistral Medium does, with 262K tokens against 131K.

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

25 benchmarks have published results for both models. gpt-oss-20b has 34 scored results on Noometry and Mistral Medium has 36.

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