SpaceXAI: Grok 4.6 vs OpenAI: GPT-5.6 Luna (batch)

For a sample job of 1 million input tokens and 250,000 output tokens, GPT-5.6 Luna (batch) costs $0.25 and Grok 4.6 costs $3.50, so GPT-5.6 Luna (batch) is about 14.0 times cheaper for the same work.

GPT-5.6 Luna (batch) reads up to 1,050,000 tokens at once, roughly 1,575 pages of text, against about 750 pages for Grok 4.6.

On our blended benchmark score Grok 4.6 leads 75.3 to 62.3.

Across the 20 tasks where they differ, Grok 4.6 scores higher on 13 (SQL Generation, Code Review, Code Refactoring and others), GPT-5.6 Luna (batch) on 7 (Code Completion, Code Documentation, Regex Writing and others).

Grok 4.6 was released in August 2026 and GPT-5.6 Luna (batch) in July 2026.

Pick Grok 4.6 if you need benchmark performance; pick GPT-5.6 Luna (batch) if you need lower cost or long documents.

Costs use current list prices per million tokens; page counts assume about 0.75 words per token and 500 words per page.