GPT-6 Astra vs GPT-6 Luna: cost per task
GPT-6 Luna is cheaper on 14 of 14 tasks and about 92.7x cheaper on average (geometric mean). GPT-6 Astra has the higher LMArena Text score (1477 vs 1443).
| Task | GPT-6 Astra | GPT-6 Luna | Difference |
|---|---|---|---|
| Answer a chat question | 3.4¢ | 0.06¢ | 56.6x |
| Reply to a customer email | 0.89¢ | <0.01¢ | 122.0x |
| Write a 1,500-word blog post | 11¢ | 0.12¢ | 97.0x |
| Write 10 product descriptions | 6.2¢ | 0.05¢ | 114.3x |
| Translate 1,000 words | 8.0¢ | 0.08¢ | 96.3x |
| Proofread one page (500 words) | 4.0¢ | 0.04¢ | 89.7x |
| Summarize a 20-page PDF | 16¢ | 0.16¢ | 99.2x |
| Extract data from an invoice | 2.6¢ | 0.03¢ | 82.4x |
| Analyze a 200-row spreadsheet | 42¢ | 0.19¢ | 224.8x |
| Answer from 5 retrieved documents (RAG) | 5.9¢ | 0.05¢ | 109.7x |
| Classify 100 support tickets | 3.9¢ | 0.06¢ | 59.9x |
| Review 500 lines of code | 24¢ | 0.31¢ | 79.3x |
| Write a SQL query | 2.4¢ | 0.04¢ | 60.0x |
| Run a 50-step coding agent | $3.72 | 4.1¢ | 91.4x |
Specs and list prices
| GPT-6 Astra | GPT-6 Luna | |
|---|---|---|
| Input per 1M | $10.00 | $0.10 |
| Output per 1M | $50.00 | $0.50 |
| Cached input per 1M | $1.00 | $0.01 |
| Context | 1.05M | 1.05M |
| Providers | 7 | 7 |
| Reasoning | always | default |
| LMArena Text | 1477 | 1443 |
| Released | Sep 4, 2026 | Sep 22, 2026 |
FAQ
Is GPT-6 Astra or GPT-6 Luna cheaper?
GPT-6 Luna is cheaper on 14 of 14 tasks and about 92.7x cheaper on average (geometric mean). GPT-6 Astra has the higher LMArena Text score (1477 vs 1443).
How much does GPT-6 Astra cost compared to GPT-6 Luna per token?
GPT-6 Astra: $10.00 input and $50.00 output per 1M tokens. GPT-6 Luna: $0.10 input and $0.50 output. Token prices alone mislead - models use different numbers of tokens for the same task, which is what the task table shows.