Hermes 4 405B Open vs 
GPT-5.6 Luna Paid
Hermes 4 405B vs GPT-5.6 Luna compared — price per token, context window, multimodality, openness and which to choose. Can the open-source model replace the paid one? Full 2026 breakdown.
Prices & specs refreshed from live data · olud.ai
Open-model prices = cheapest provider via OpenRouter; official maker rates may be higher.
Hermes 4 405B vs GPT-5.6 Luna specs
| Spec | Hermes 4 405B | GPT-5.6 Luna |
|---|---|---|
| Maker | Nous Research | OpenAI |
| Type | Open-weight | Proprietary |
| Context window | 131K tokens | 1.1M tokens |
| Input price | $1/M · free self-host | $0.5/M |
| Output price | $3/M · free self-host | $3/M |
| Vision / multimodal | No | Yes |
| Tool / function calling | No | Yes |
| Self-hostable | Yes | No (API only) |
| License | Open weights | Proprietary |
Feature comparison
| Capability | Hermes 4 405B | GPT-5.6 Luna |
|---|---|---|
| Open weights (downloadable) | ✓ | ✗ |
| Self-hostable | ✓ | ✗ |
| Runs fully offline | ✓ | ✗ |
| Vision / multimodal | ✗ | ✓ |
| Tool / function calling | ✗ | ✓ |
| 1M+ context window | ✗ | ✓ |
Benchmarks: Hermes 4 405B vs GPT-5.6 Luna
Independent benchmark scores measured by Artificial Analysis. Higher is better (except latency).
Benchmark data by Artificial Analysis.
How Hermes 4 405B and GPT-5.6 Luna score
| Criterion | Hermes 4 405B | GPT-5.6 Luna |
|---|---|---|
| Cost-efficiency | 4.0 | 4.0 |
| Context window | 3.5 | 5.0 |
| Openness | 5.0 | 1.5 |
| Self-hosting | 5.0 | 1.0 |
| Multimodality | 2.0 | 5.0 |
Scores come from live data — output price (cost), context length, open vs closed weights (openness & self-hosting) and vision/tool support (multimodality). Raw task quality isn't scored here; it depends on your benchmark — see the verdict.
What each model is
Hermes 4 405B Open
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...
GPT-5.6 Luna Paid
GPT-5.6 Luna is a fast, cost-efficient model in OpenAI's GPT-5.6 series. It is suited for high-volume, latency-sensitive tasks such as chat, classification, and lightweight agentic workflows, providing capable reasoning for...
Other models in these families
These variants are tracked but not compared here — one page per family keeps the comparison readable.
Frequently asked questions
Is Hermes 4 405B as good as GPT-5.6 Luna?
Hermes 4 405B is open-weight and competitive on many tasks, but GPT-5.6 Luna may still lead on the hardest reasoning and agentic work. The gap keeps narrowing — benchmark both on your actual use case before deciding.
Can I run Hermes 4 405B locally?
Yes. Hermes 4 405B has open weights, so you can self-host it on your own GPUs or run it via a low-cost API. GPT-5.6 Luna is API-only and cannot be self-hosted.
Hermes 4 405B vs GPT-5.6 Luna — which should I pick in 2026?
Choose Hermes 4 405B if you want to self-host, keep your data private and skip per-token fees — it's open-weight and runs on your own hardware. Choose GPT-5.6 Luna if you want frontier capability through a managed API with zero infrastructure to run.
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