Grok 4.5 Paid vs 
GPT-5.6 Luna Paid
Grok 4.5 vs GPT-5.6 Luna compared — price per token, context window, multimodality, openness and which to choose. Full 2026 breakdown.
Grok 4.5 — full profile › · GPT-5.6 Luna — full profile ›
Prices & specs refreshed from live data · OpenSourceAI.tech
Open-model prices = cheapest provider via OpenRouter; official maker rates may be higher.
Grok 4.5 vs GPT-5.6 Luna specs
| Spec | Grok 4.5 | GPT-5.6 Luna |
|---|---|---|
| Maker | xAI | OpenAI |
| Type | Proprietary | Proprietary |
| Context window | 500K tokens | 1.1M tokens |
| Input price | $2/M | $1/M |
| Output price | $6/M | $6/M |
| Vision / multimodal | Yes | Yes |
| Tool / function calling | Yes | Yes |
| Self-hostable | No (API only) | No (API only) |
| License | Proprietary | Proprietary |
Feature comparison
| Capability | Grok 4.5 | GPT-5.6 Luna |
|---|---|---|
| Open weights (downloadable) | ✗ | ✗ |
| Self-hostable | ✗ | ✗ |
| Runs fully offline | ✗ | ✗ |
| Vision / multimodal | ✓ | ✓ |
| Tool / function calling | ✓ | ✓ |
| 1M+ context window | ✗ | ✓ |
Benchmarks: Grok 4.5 vs GPT-5.6 Luna
Independent benchmark scores measured by Artificial Analysis. Higher is better (except latency).
Benchmark data by Artificial Analysis.
How Grok 4.5 and GPT-5.6 Luna score
| Criterion | Grok 4.5 | GPT-5.6 Luna |
|---|---|---|
| Cost-efficiency | 4.0 | 4.0 |
| Context window | 4.5 | 5.0 |
| Openness | 1.5 | 1.5 |
| Self-hosting | 1.0 | 1.0 |
| Multimodality | 5.0 | 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
Grok 4.5 Paid
Grok 4.5 is SpaceXAI's smartest model with frontier performance on coding, knowledge work, and STEM.
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
Grok 4.5 vs GPT-5.6 Luna — which is cheaper?
Grok 4.5 is cheaper on output ($6/M vs $6/M).
Which has the larger context window?
GPT-5.6 Luna offers the larger context window (1.1M tokens).
Grok 4.5 vs GPT-5.6 Luna — which should I pick in 2026?
Choose Grok 4.5 for the lower output price ($6/M vs $6/M). Choose GPT-5.6 Luna if you need the larger 1.1M context window.
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