text model comparison
GPT-5.5 vs GPT-6 Astra
GPT-5.5 and GPT-6 Astra are both current text models, from OpenAI. GPT-5.5 is 50% cheaper per 1M input tokens than GPT-6 Astra, $5 vs $10. On Arena Text, GPT-5.5 scores 1482 Elo and GPT-6 Astra 1475 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-5.5 | GPT-6 Astra |
|---|---|---|
| Price per 1M input tokens | $5 (better) | $10 |
| Price per 1M output tokens | $30 (better) | $50 |
| Cost of 10M input and 2M output tokens | $110 (better) | $200 |
| Arena Text | 1482 Elo (#13 of 39) (better) | 1475 Elo (#18 of 39) |
| GPQA Diamond | 90.7% (#21 of 37) | 95.8% (#1 of 37) (better) |
| FrontierMath Tiers 1-3 (v2) | 85.3% (#11 of 37) | 93.7% (#1 of 37) (better) |
| SimpleQA Verified | 63% (#13 of 34) | 75.6% (#1 of 34) (better) |
| LiveBench Overall | 79.91 points (#1 of 5) | Not measured |
| Provider | OpenAI | OpenAI |
| Release date | April 23, 2026 | September 3, 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 |
Scores:Arena · 2026-10-12Epoch AI · 2026-10-12LiveBench · 2026-06-25
When to choose each
GPT-5.5
Best for
- High-capability API evaluations with long context
Watch out for
- Prompts above the provider long-context threshold use higher token rates; validate the selected reasoning effort against production cost
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-5.5 vs GPT-6 Astra FAQ
Which is cheaper, GPT-5.5 or GPT-6 Astra?
GPT-5.5 is 50% cheaper per 1M input tokens than GPT-6 Astra, $5 vs $10. For 10M input and 2M output tokens, GPT-5.5 costs $110 and GPT-6 Astra $200 at standard rates.
Which scores higher on independent benchmarks, GPT-5.5 or GPT-6 Astra?
GPT-5.5 leads on Arena Text, 1482 Elo to 1475 Elo; GPT-6 Astra leads on GPQA Diamond, 95.8% to 90.7%; GPT-6 Astra leads on FrontierMath Tiers 1-3 (v2), 93.7% to 85.3%. Scores are independent evaluations, not either vendor's launch figures.
Which has the larger context window, GPT-5.5 or GPT-6 Astra?
Both accept 1,050,000 tokens of context.
Related comparisons
Production evaluation
Choosing between GPT-5.5 and GPT-6 Astra?
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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