GPT OSS 120B

by OpenAI

GPT OSS 120B is a model from OpenAI, released on August 5, 2025. It has a 131K-token context window and can generate up to 131K output tokens. API pricing is $0.04 per 1M input tokens and $0.17 per 1M output tokens. It ranks #88 of 220 models by Intelligence Score with a score of 28.5.

GPT-OSS-120B is an open-weight, 116.8B-parameter Mixture-of-Experts (MoE) language model from OpenAI 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. It achieves near-parity with OpenAI o4-mini on core reasoning benchmarks. Note: While referred to as '120b' for simplicity, it technically has 116.8B parameters.

Key specs

ProviderOpenAI
Release date2025-08-05
Licenseopen source
Context window131K tokens
Max output131K tokens
Input price$0.04 / 1M tokens
Output price$0.17 / 1M tokens
Intelligence Score28.5

Quick answers

What is the context window of GPT OSS 120B?

GPT OSS 120B has a context window of 131K tokens, with a maximum output of 131K tokens per response.

How much does GPT OSS 120B cost?

GPT OSS 120B costs $0.04 per 1M input tokens and $0.17 per 1M output tokens through the API.

Is GPT OSS 120B open source?

Yes. GPT OSS 120B is an open model released under the open source license.

When was GPT OSS 120B released?

OpenAI released GPT OSS 120B on August 5, 2025.

How does GPT OSS 120B compare to Claude Opus 5.5 (Reasoning)?

GPT OSS 120B scores 28.5 on the Intelligence Score versus 60.5 for Claude Opus 5.5 (Reasoning), the current #1. Input pricing is $0.04 vs $4 per 1M tokens.

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