gpt-oss-20b
OpenAI • LLM
gpt-oss-20b is an open-weight 21B parameter model released by OpenAI under the Apache 2.0 license. It uses a Mixture-of-Experts (MoE) architecture with 3.6B active parameters per forward pass, optimized for...
Specifications
Context Window
131K tokens
Input Price/1M
$0.06
Output Price/1M
$0.20
Parameters
—
Speed
273 tok/s
Latency (TTFT)
489ms
Max Output
131K tokens
Benchmarks
gpt-oss-20b results on the main AI model evaluation benchmarks. Higher scores indicate better performance.
Agentic
| Benchmark | Score | Maximum | Methodology |
|---|---|---|---|
| Terminal-Bench Hard | 11.0 | 100.0 | — |
Coding
| Benchmark | Score | Maximum | Methodology |
|---|---|---|---|
| LiveCodeBench | 78.0 | 100.0 | Artificial Analysis official API |
| SciCode | 34.0 | 100.0 | — |
| AA Coding Index | 18.5 | 100.0 | Artificial Analysis official API |
Knowledge
| Benchmark | Score | Maximum | Methodology |
|---|---|---|---|
| MMLU-Pro | 75.0 | 100.0 | — |
Long Context
| Benchmark | Score | Maximum | Methodology |
|---|---|---|---|
| AA-LCR | 31.0 | 100.0 | — |
Math
| Benchmark | Score | Maximum | Methodology |
|---|---|---|---|
| AA Math Index | 89.3 | 100.0 | Artificial Analysis official API |
| AIME 2025 | 89.0 | 100.0 | Artificial Analysis official API |
overall
| Benchmark | Score | Maximum | Methodology |
|---|---|---|---|
| AA Intelligence Index | 24.5 | 100.0 | Artificial Analysis official API |
Reasoning
| Benchmark | Score | Maximum | Methodology |
|---|---|---|---|
| MMLU Pro | 71.8 | 100.0 | Artificial Analysis official API |
| GPQA Diamond | 69.0 | 100.0 | Artificial Analysis official API |
| IFBench | 65.0 | 100.0 | — |
| HLE | 10.0 | 100.0 | — |
Tool Use
| Benchmark | Score | Maximum | Methodology |
|---|---|---|---|
| Tau²-Bench | 60.0 | 100.0 | — |
Information
- Release date
- August 05, 2025
- Tool Calling
- ✅ Supported
- Vision
- ❌ Not supported
- Audio
- ❌ Not supported
Full Analysis: gpt-oss-20b
What is gpt-oss-20b?
gpt-oss-20b is an AI model developed by OpenAI, classified as a large language model (LLM). It focuses on text processing and natural language generation. As a proprietary model, it is available via OpenAI's cloud API. With a context window of 131K tokens, it is suitable for processing long documents such as contracts, books, and complete codebases.
Pricing & Costs in 2026
gpt-oss-20b is usage-based, priced at $0.06/1M input tokens and $0.2/1M output tokens. For context: 1 million tokens is approximately 750,000 words, or about 10 average-length books. At this aggressive price point, it is one of the most cost-effective options on the market, ideal for high-volume applications like chatbots, bulk document analysis, and automation.
Benchmarks & Performance
gpt-oss-20b was evaluated on 14 different benchmarks, covering categories like Agentic, Coding, Knowledge, Long Context, Math, overall, Reasoning, Tool Use. Results show solid performance across available evaluations.
It's important to note that benchmarks measure specific aspects and don't capture the full user experience. Factors like instruction adherence, behavior in long conversations, and real-world task quality vary significantly between models and aren't always reflected in standard scores.
Recommended Use Cases
gpt-oss-20b is suitable for a wide range of AI applications: long document analysis (contracts, legal proceedings, codebases), automation with tool calling (API integration, databases, external systems), high-volume chatbots and automated support, complex reasoning, math problem solving, and logical analysis, text generation, summarization, translation, and general assistance.
Comparison with Alternatives
In the 2026 AI model ecosystem, gpt-oss-20b competes directly with similarly capable models. Key competitors include Claude (Anthropic), Gemini (Google), and open source models like Llama (Meta) and Qwen (Alibaba). The choice between models depends on the specific use case, budget, latency requirements, and need for features like multimodality and tool calling.
For a detailed side-by-side comparison, use our comparison tool or check the overall model ranking.
Frequently Asked Questions
What is gpt-oss-20b?
gpt-oss-20b is an open-weight 21B parameter model released by OpenAI under the Apache 2.0 license. It uses a Mixture-of-Experts (MoE) architecture with 3.6B active parameters per forward pass, optimized for...
How much does gpt-oss-20b cost?
gpt-oss-20b costs $0.06/1M input tokens and $0.2/1M output tokens. For heavy usage (e.g., a chatbot handling 100k messages/month), costs can range from $10 to $1,000 depending on volume.
How does gpt-oss-20b compare with other models?
In available benchmarks, gpt-oss-20b scored: Terminal-Bench Hard: 11/100, LiveCodeBench: 78/100, SciCode: 34/100. See the full table above for a detailed comparison.
Is gpt-oss-20b open source?
No, gpt-oss-20b is a proprietary model from OpenAI. It is available via cloud API. For open source alternatives, check our open source model ranking.
What is gpt-oss-20b best for?
gpt-oss-20b excels at complex reasoning and problem solving. With its large context window, it handles long documents, codebases, and extended conversations. It supports tool calling for API integrations and automation.
Last updated: June 01, 2026 • View methodology →