gpt-oss-20b | Epoch AI

ECI#143

135

OpenAI

Aug. 5, 2025

Open weights

gpt-oss-20b is an open-weights model from OpenAI, released August 5, 2025. It has an ECI score of 135 and ranks 143rd of 240 tracked models. At the time of its release, it ranked 36th of 133 tracked models.

gpt-oss-20b vs select alternatives

Domain	Benchmark	gpt-oss-20b OpenAI Aug. 5, 2025 Open weights	GPT-4.1 mini OpenAI Apr. 14, 2025 Closed weights	o1-mini OpenAI Sep. 12, 2024 Closed weights	Qwen3-30B-A3B-Instruct (Jul 2025) Alibaba Jul. 29, 2025 Open weights
	ECI scoreBest score 173	135	134	135	135
	Ranking	#143	#144	#140	#142
Conceptual reasoning	LMCABest score 70.6	14.5	21.1	—	22.4
	DTBenchBest score 99%	68%	69%	n/a	67%
Mathematics	OTIS Mock AIME 2024-2025Best score 100%	65%	45%	47%	62%
Science	CritPt v1Best score 36%	1%	0%	n/a	n/a
	SciCodeBest score 68%	39%	40%	n/a	n/a
	GPQA DiamondBest score 97%	61%	66%	62%	56%
Software engineering	WeirdML (v2)Best score 94%	41%	38%	36%	n/a

Model metadata

General
Organization	OpenAI
Release date	Aug. 5, 2025
Model accessibility	Open weights
Country	United States of America
Knowledge cutoff	Unknown
Provider notes	gpt-oss-120b & gpt-oss-20b Model Card

Pricing
Input price	$0.04 / 1M tokens
Output price	$0.15 / 1M tokens

Training
Parameters	2.1e10
Training compute	5.5e23 FLOP
Training hardware	NVIDIA H100 SXM5 80GB
Training time	Unknown
Training dataset size	Unknown