Language

gpt-oss-20b

Released
5 Aug 2025
Status
Current
Context
131.1K
Max output
131.1K
Input per 1M tokens
—
Output per 1M tokens
—
Open weights
Yes
License
apache-2.0
Parameters
21B, 3.6B active
Knowledge cutoff
Jun 2024
Reasoning
Yes
Modalities
text → text

Category scores

Out of 100, from independent and third-party results only, by method category-2026-09-29.1.

Category scores
CategoryScoreRankCoverage
Knowledge & reasoning8.5992 of 4
Human preference38.4Not ranked1 of 5

Benchmark results

Every result we hold for this model, with who ran it and where it was published.

Knowledge & reasoning

Knowledge & reasoning results
BenchmarkMetricValueProvenanceSettingEvaluatedSource
Chess PuzzlesPuzzles solved4.0%Independentmedium27 Aug 2026Epoch AI
Chess PuzzlesPuzzles solved2.0%Independentlow27 Aug 2026Epoch AI
Chess PuzzlesPuzzles solved0.0%Independenthigh27 Aug 2026Epoch AI
DTBench (Decision Theory Benchmark)Accuracy (capability questions)68.0%Third partyhigh—https://conceptualreasoning.ai/dtbench via Epoch AI
Humanity's Last Exam (HLE)Accuracy17.3%Self-reported——GPT-OSS Model Card via Hugging Face Community Evals
LMCA (Language Model Conceptual Argumentation)Correlation with expert ratings (Pearson r)0.1451Third partyhigh—https://conceptualreasoning.ai/lmca via Epoch AI
MMLU-ProAccuracy73.6%Self-reported——EvalEval via Hugging Face Community Evals

Scientific reasoning

Scientific reasoning results
BenchmarkMetricValueProvenanceSettingEvaluatedSource
GPQA DiamondAccuracy60.8%Independentmedium27 Aug 2026Epoch AI
GPQA DiamondAccuracy53.2%Independentlow27 Aug 2026Epoch AI
GPQA DiamondAccuracy46.0%Independenthigh6 Aug 2026Epoch AI
GPQA DiamondAccuracy74.2%Self-reported——GPT-OSS Model Card via Hugging Face Community Evals

Mathematics

Mathematics results
BenchmarkMetricValueProvenanceSettingEvaluatedSource
OTIS Mock AIME 2024-2025Accuracy65.3%Independentmedium27 Aug 2026Epoch AI
OTIS Mock AIME 2024-2025Accuracy50.8%Independenthigh27 Aug 2026Epoch AI
OTIS Mock AIME 2024-2025Accuracy40.3%Independentlow27 Aug 2026Epoch AI

Coding & software engineering

Coding & software engineering results
BenchmarkMetricValueProvenanceSettingEvaluatedSource
Terminal-Bench 2.0Accuracy (mean over trials)3.4%Third party——Terminal-Bench v2 Leaderboard via Epoch AI
Terminal-Bench 2.0Accuracy (mean over trials)3.4%Third partyunknown—https://www.tbench.ai/leaderboard/terminal-bench/2.0 via Epoch AI
Terminal-Bench 2.0Accuracy (mean over trials)3.1%Third party——Terminal-Bench v2 Leaderboard via Epoch AI
Terminal-Bench 2.0Accuracy (mean over trials)3.1%Third partyunknown—https://www.tbench.ai/leaderboard/terminal-bench/2.0 via Epoch AI
WeirdML (v2)Average accuracy40.9%Third partyhigh—https://htihle.github.io/weirdml.html via Epoch AI
WeirdML (v2)Average accuracy36.8%Third partymedium—https://htihle.github.io/weirdml.html via Epoch AI

Human preference

Human preference results
BenchmarkMetricValueProvenanceSettingEvaluatedSource
Text Arena (arena.ai)Arena score (Elo scale)1318Independent—25 Sep 2026Arena
Text Arena (arena.ai)Votes10372Independent—25 Sep 2026Arena

Other gpt-oss versions

Sources