NVIDIA Nemotron 3 Ultra is an open frontier-reasoning and orchestration model from NVIDIA, with 55B active parameters out of 550B total (MoE). Built on a hybrid Transformer-Mamba mixture-of-experts architecture, it...
Model details →NVIDIA: Nemotron 3 Ultra (free) vs OpenAI: GPT-5.6 Luna Pro
NVIDIA: Nemotron 3 Ultra (free) and OpenAI: GPT-5.6 Luna Pro are evenly matched on 6 axes — pick the one whose provider, latency, or licensing fits your stack.
GPT-5.6 Luna Pro is the same underlying model as [GPT-5.6 Luna](https://openrouter.ai/openai/gpt-5.6-luna), served with `reasoning.mode` set to `pro` for higher-quality responses on complex tasks. Learn more in OpenAI's docs: https://devel…
Model details →Side-by-side comparison
| Capability | NVIDIA: Nemotron 3 Ultra (free) | OpenAI: GPT-5.6 Luna Pro | Winner |
|---|---|---|---|
| Context window Maximum number of input tokens the model can attend to in a single request. | 1M | 1.1M | 🏆 OpenAI: GPT-5.6 Luna Pro |
| Input price (per 1M) Cost per million input tokens billed by the provider. | $0.00 | $0.10 | 🏆 NVIDIA: Nemotron 3 Ultra (free) |
| Output price (per 1M) Cost per million output tokens billed by the provider. | $0.00 | $0.60 | 🏆 NVIDIA: Nemotron 3 Ultra (free) |
| Tool / function calling First-class support for emitting structured tool calls. | Yes | Yes | Tie |
| Vision input Accepts image inputs alongside text. | — | Yes | 🏆 OpenAI: GPT-5.6 Luna Pro |
| Reasoning mode Internal chain-of-thought / extended-thinking support. | Yes | Yes | Tie |
Frequently asked questions
Is NVIDIA: Nemotron 3 Ultra (free) better than OpenAI: GPT-5.6 Luna Pro?
NVIDIA: Nemotron 3 Ultra (free) and OpenAI: GPT-5.6 Luna Pro are evenly matched on 6 axes — pick the one whose provider, latency, or licensing fits your stack.
What's the price difference between NVIDIA: Nemotron 3 Ultra (free) and OpenAI: GPT-5.6 Luna Pro?
Input: $0.00 vs $0.10 per 1M tokens. Output: $0.00 vs $0.60 per 1M tokens.
What context windows do NVIDIA: Nemotron 3 Ultra (free) and OpenAI: GPT-5.6 Luna Pro support?
NVIDIA: Nemotron 3 Ultra (free) supports up to 1M tokens. OpenAI: GPT-5.6 Luna Pro supports up to 1.1M tokens.
Do both NVIDIA: Nemotron 3 Ultra (free) and OpenAI: GPT-5.6 Luna Pro support tool calling?
NVIDIA: Nemotron 3 Ultra (free): yes. OpenAI: GPT-5.6 Luna Pro: yes.
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