text model comparison
GPT-6 Astra vs GPT-6 Luna
GPT-6 Astra and GPT-6 Luna are both current text models, from OpenAI. GPT-6 Luna is 99% cheaper per 1M input tokens than GPT-6 Astra, $0.10 vs $10. On Arena Text, GPT-6 Astra scores 1475 Elo and GPT-6 Luna 1443 Elo (Arena, measured October 8, 2026). Both accept 1,050,000 tokens of context.
Data verified October 12, 2026 · Dataset 2026-10-12
Side by side
Standard-tier prices in effect today. The better value in each row is highlighted.
| Fact | GPT-6 Astra | GPT-6 Luna |
|---|---|---|
| Price per 1M input tokens | $10 | $0.10 (better) |
| Price per 1M output tokens | $50 | $0.50 (better) |
| Cost of 10M input and 2M output tokens | $200 | $2 (better) |
| Arena Text | 1475 Elo (#18 of 39) (better) | 1443 Elo (#31 of 39) |
| GPQA Diamond | 95.8% (#1 of 37) (better) | 90.5% (#23 of 37) |
| FrontierMath Tiers 1-3 (v2) | 93.7% (#1 of 37) (better) | 78.9% (#14 of 37) |
| SimpleQA Verified | 75.6% (#1 of 34) (better) | 41.4% (#25 of 34) |
| Provider | OpenAI | OpenAI |
| Release date | September 3, 2026 | September 22, 2026 |
| Access | API only | API only |
| Context window | 1,050,000 tokens | 1,050,000 tokens |
| Max output | 128,000 tokens | 128,000 tokens |
| Input | text, image | text, image |
| Output | text | text |
When to choose each
GPT-6 Astra
Best for
- Frontier reasoning and agentic evaluations where deep-context retrieval accuracy is the binding constraint
- Workloads that can be kept under the long-context threshold, where the effective rate stays at $10 / $50
Watch out for
- Long-context billing is a cliff, not a taper: a request over the long-context threshold is rebilled in full at $20 per million input and $75 per million output, so a prompt that crosses it costs roughly double
- GPT-6 Astra is the first publicly released model OpenAI classifies as crossing the Critical cybersecurity threshold under its own Preparedness Framework, which carries additional deployment safeguards
- Vendor-reported benchmark figures come from OpenAI’s own launch material and its own harness; they are not independently reproduced here
GPT-6 Luna
Best for
- High-volume summarisation, extraction and routing
- Long-context budget work, where the 272k threshold is more forgiving than Haiku 5.5's 100k
Watch out for
- Prompts over 272,000 tokens are rebilled at $0.20 input and $0.75 output for the whole request
- A twentieth of GPT-6 Sol's price reflects a capability gap, not a discount on the same model
GPT-6 Astra vs GPT-6 Luna FAQ
Which is cheaper, GPT-6 Astra or GPT-6 Luna?
GPT-6 Luna is 99% cheaper per 1M input tokens than GPT-6 Astra, $0.10 vs $10. For 10M input and 2M output tokens, GPT-6 Astra costs $200 and GPT-6 Luna $2 at standard rates.
Which scores higher on independent benchmarks, GPT-6 Astra or GPT-6 Luna?
GPT-6 Astra leads on Arena Text, 1475 Elo to 1443 Elo; GPT-6 Astra leads on GPQA Diamond, 95.8% to 90.5%; GPT-6 Astra leads on FrontierMath Tiers 1-3 (v2), 93.7% to 78.9%. Scores are independent evaluations, not either vendor's launch figures.
Which has the larger context window, GPT-6 Astra or GPT-6 Luna?
Both accept 1,050,000 tokens of context.
Related comparisons
Production evaluation
Choosing between GPT-6 Astra and GPT-6 Luna?
Public benchmarks narrow the shortlist. We run both on your own tasks, data and cost limits, then build the routing and review controls to run the winner in production.
- A head-to-head evaluation on your real workload
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