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gpt-oss-20b

OpenAI · 2025-08-05

gpt-oss-20b is OpenAI's smaller open-weight reasoning model in the Apache 2.0-licensed gpt-oss family, sized for lower-latency, local, or specialized use cases. It is a text-only Mixture-of-Experts model with 21B total parameters and 3.6B active parameters per token, configurable reasoning effort, and tool-use support.

Benchmark scores

BenchmarkScore
AA-Briefcase Elo-36.8
AA-LCR31.0
AA-Omniscience Index-60.1
AIME 2024 (avg@8)86.7
AIME 2024-202586.0
AIME 202562.3
AIME 2025 (avg@8)85.4
ALE-Bench942
APEX-Agents-AA0.7
Arena Text — Business, Management & Financial Ops (No Style Control)1283
Arena Text — Chinese (No Style Control)1309
Arena Text — Creative Writing (No Style Control)1199
Arena Text — English (No Style Control)1302
Arena Text — Entertainment, Sports & Media (No Style Control)1218
Arena Text — Exclude Ties (No Style Control)1223
Arena Text — Exclude Ties (Style Controlled)1262
Arena Text — Expert (No Style Control)1261
Arena Text — German (No Style Control)1251
Arena Text — Hard Prompts (No Style Control)1274
Arena Text — Hard Prompts English (No Style Control)1292
Arena Text — Instruction Following (No Style Control)1238
Arena Text — Japanese (No Style Control)1249
Arena Text — Korean (No Style Control)1249
Arena Text — Legal & Government (No Style Control)1281
Arena Text — Life, Physical & Social Science (No Style Control)1297
Arena Text — Longer Query (No Style Control)1250
Arena Text — Medicine & Healthcare (No Style Control)1311
Arena Text — Multi-turn (No Style Control)1271
Arena Text — Non-English (No Style Control)1269
Arena Text — Non-English (Style Controlled)1299
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