GPT-5.6 Luna VS Grok 4.5
OpenAI · xAI · AI Models · Updated Jul 26, 2026
Side-by-Side Breakdown
| Feature | GPT-5.6 Luna | Grok 4.5 | Winner |
|---|---|---|---|
| Input Price | $1.00/1M tkns | $2.00/1M tkns | ✓ GPT-5.6 Luna |
| Output Price | $6.00/1M tkns | $6.00/1M tkns | — |
| Provider | OpenAI | xAI | — |
| Category | ai-model | ai-model | — |
| context window | 1050000 | 500000 | |
| modalities | text+image+file->text | text+image+file->text | |
| vision | true | true | |
| Overall Winner | 🏆 | GPT-5.6 Luna |
GPT-5.6 Luna vs Grok 4.5: Quick Summary
GPT-5.6 Luna is the more affordable choice. GPT-5.6 Luna costs $1.00/1M tkns vs Grok 4.5 at $2.00/1M tkns (Input Price). GPT-5.6 Luna is 50.0% cheaper. Pricing verified as of Jul 26, 2026 — always confirm on the provider's official pricing page before committing.
GPT-5.6 Luna vs Grok 4.5: Full Pricing Analysis
On headline price, GPT-5.6 Luna is the cheaper option: $1.00/1M tkns versus $2.00/1M tkns for Grok 4.5 (Input Price) — about 50% less. At a scale of one million per 1M tokens, that difference works out to roughly $1,000.00 with GPT-5.6 Luna against $2,000.00 with Grok 4.5. For high-volume workloads that gap compounds quickly, so if your usage is predictable and large, GPT-5.6 Luna is the more economical default.
Price isn’t the whole story, though. Grok 4.5 (xAI) sits at the higher price point, which is often justified by broader features, stronger delivery/SLA guarantees, or a more mature developer experience. If you need those capabilities, the premium can pay for itself. Choose GPT-5.6 Luna when cost-per-unit is the priority and your requirements are straightforward; choose Grok 4.5 when reliability, tooling, or ecosystem fit matter more than shaving the per-unit rate.
Beyond price, the two differ on context window (1050000 vs 500000), modalities (text+image+file->text vs text+image+file->text) and vision (true vs true). Check those specs against your actual requirements before committing — the cheaper option is only the better deal if it also meets your technical needs.
Pricing shown is Input Price as published by each provider and verified Jul 26, 2026. Providers change prices and introduce free tiers and volume discounts frequently — always confirm the current rate on OpenAI’s and xAI’s official pricing pages before you commit.