Hermes 4 405B: Pricing, Context Window & Benchmarks
405Bby Nous
Hermes 4 is a large-scale reasoning model built on Meta-Llama-3.1-405B and released by Nous Research. It introduces a hybrid reasoning mode, where the model can choose to deliberate internally with <think>...</think> traces or respond directly, offering flexibility between speed and depth. Users can control the reasoning behaviour with the `reasoning` `enabled` boolean. [Learn more in our docs](https://openrouter.ai/docs/use-cases/reasoning-tokens#enable-reasoning-with-default-config) The model is instruction-tuned with an expanded post-training corpus (~60B tokens) emphasizing reasoning traces, improving performance in math, code, STEM, and logical reasoning, while retaining broad assistant utility. It also supports structured outputs, including JSON mode, schema adherence, function calling, and tool use. Hermes 4 is trained for steerability, lower refusal rates, and alignment toward neutral, user-directed behavior.
What you can do with Hermes 4 405B
Everyday Q&A and clear explanations
Writing help (emails, posts, summaries)
Idea generation and brainstorming
Learning support with step-by-step guidance
Benchmarks not available
This model isn't listed on Artificial Analysis yet. Showing OpenRouter specs below.
| Metric | Value |
|---|---|
| Provider | Nous |
| Context Window | 131,072 tokens |
| Input Price | $1.00/1M tokens |
| Output Price | $3.00/1M tokens |
| Release Date | Aug 26, 2025 |
| Modalities | text |
| Capabilities | N/A |
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Frequently asked questions
What is Hermes 4 405B good for?
Use Hermes 4 405B for everyday tasks like writing, summarizing, brainstorming, and getting clear explanations.
How much does Hermes 4 405B cost?
Pricing is based on usage. Current rates are $1.00/1M tokens for input and $3.00/1M tokens for output.
Can I try Hermes 4 405B for free?
Yes. You can start a chat instantly and test the model before deciding on a plan.
Does Hermes 4 405B support images or audio?
Hermes 4 405B focuses on text-based tasks.
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