OpenAI · Open weights
GPT OSS 120B
An open-weight, 117B-parameter Mixture-of-Experts (MoE) language model designed for high-reasoning, agentic, and general-purpose production use cases. It activates 5.1B parameters per forward pass and is optimized to run on a single H100 GPU with native MXFP4 quantization. The model supports configurable reasoning depth, full chain-of-thought access, and native tool use, including function calling, browsing, and structured output generation.
- Reasoning
- Tools
- Structured output
- Input
- Text
- Output
- Text
- Discovery tier
- Open weights
Pricing
USD per 1M tokens- Input
- $0.03
- Output
- $0.15
- Cache read
- $0.03
Reference prices as published by the model provider. API example
Specifications
- Context window
- 128K
- Max output
- 16.4K
- Average output (7 days)
- 1.1K tokens
- Longer than 74% of 468 models
Side by side
Compare models
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Public evaluations
Benchmarks
Independent evaluation results, with how each score ranks among the models in the Noumen catalog.
Intelligence Index
11.6
Tested at high reasoning effort
Better than 25% of 326 scored models
Indexes
Coding Index
30.4Composite of the coding evaluations
Better than 22% of 168 scored models
Math Index
93.4Composite of the math evaluations
Better than 93% of 118 scored models
Agentic work
AutomationBench-AA
0.2%Workflow automation, penalized for guardrail violations
Better than 2% of 173 scored models
AutomationBench-AA tasks completed
0.0%Workflows finished end to end without a guardrail violation
Better than 0% of 173 scored models
GDPval-AAv2.1
608 EloEconomically valuable occupational tasks, rated head to head
Better than 16% of 187 scored models
Document reasoning
GDP.pdf
4.0%Professional reasoning over PDF documents, all-pass rate
Better than 17% of 171 scored models
AA-LCRv1.1
52.0%Reasoning across long documents
Better than 30% of 309 scored models
MLCR-AA
1.7%Long-context reasoning over medical records
Better than 3% of 121 scored models
Reasoning and knowledge
Humanity’s Last Exam
19.6%Expert-level questions across academic fields
Better than 47% of 323 scored models
GPQA Diamond
78.2%Graduate-level science questions
Better than 43% of 291 scored models
MMLU-Pro
80.8%Multi-subject knowledge and reasoning
Better than 53% of 132 scored models
IFBench
69.0%Following precise output instructions
Better than 69% of 215 scored models
Coding
Terminal-Benchv4.0
0.0%Practical software engineering in a terminal
Better than 0% of 171 scored models
SciCode
34.0%Scientific computing in Python
Better than 10% of 174 scored models
LiveCodeBench
87.8%Recent competitive programming problems
Better than 96% of 129 scored models
Math
AIME 2025
93.4%Competition mathematics, 2025 problems
Better than 93% of 118 scored models
Legacy evaluations
Terminal-Bench Hard
23.5%Earlier terminal task suite
Better than 44% of 212 scored models
τ²-Bench Telecom
65.8%Tool use in a customer-support simulation
Better than 50% of 214 scored models
AA-LCR (unversioned)
52.0%Long-context reasoning, earlier grading
Better than 30% of 309 scored models
Scores from Artificial Analysis, updated Oct 26, 2026. GPT OSS 120B was tested at high reasoning effort; compare scores measured at the same effort.Artificial Analysis
Live routing data
Performance and reliability
Recent averages across requests routed for this model. Your own speed depends on prompt length, reasoning effort and load.
- Throughput
- 126.6 tok/s
- Faster than 73% of 256 models
- Time to first token
- 0.8 s
- Quicker than 99% of 256 models
- Prompt cache hits
- 7.1%
- About $0.03 per 1M input tokens with caching
- Request success (24h)
- 99.8%
- Reliable
Cache hits are the share of input tokens recently served from a prompt cache across all requests. They are not a forecast of your own hit rate.
- Healthy (98% or more)
- Degraded (90–98%)
- Down (under 90%)
- No requests
Developers
Use it through the API
Noumen’s API is OpenAI-compatible: any Chat Completions client works with a base URL and a key.
curl https://www.noumen.xyz/api/v1/chat/completions \
-H "Authorization: Bearer $NOUMEN_API_KEY" \
-H "Content-Type: application/json" \
-d '{
"model": "openai/gpt-oss-120b",
"messages": [{ "role": "user", "content": "Explain this stack trace." }]
}'import os
from openai import OpenAI
client = OpenAI(base_url="https://www.noumen.xyz/api/v1", api_key=os.environ["NOUMEN_API_KEY"])
reply = client.chat.completions.create(
model="openai/gpt-oss-120b",
messages=[{"role": "user", "content": "Explain this stack trace."}],
)
print(reply.choices[0].message.content)OpenAI
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