GPT-5.5 Pro vs GPT-6 Astra Pro
Price, context window & benchmark comparison
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Verdict: GPT-6 Astra Pro is 3.4× cheaper than GPT-5.5 Pro on a typical 3:1 input/output mix.
| GPT-5.5 Pro | GPT-6 Astra Pro | |
|---|---|---|
| Input price / 1M | $30.00 | $10.00 |
| Output price / 1M | $180.00 | $50.00 |
| Blended price (3:1) | $67.50 | $20.00 |
| Cached input / 1M | — | $1.00 |
| Context window | 1.1M | 1.1M |
| Max output | 128K | 128K |
| Intelligence index | — | — |
| Coding index | — | — |
| Providers | — | 5 |
| Best provider uptime (30m) | — | 100.0% |
| Vision input | Yes | Yes |
| Reasoning | Yes | Yes |
| Tool calling | Yes | Yes |
| Released | 2026-04-24 | 2026-09-04 |
| Retirement | — | — |
Cost calculator
FAQ
Which is cheaper, GPT-5.5 Pro or GPT-6 Astra Pro?
GPT-6 Astra Pro is 3.4× cheaper than GPT-5.5 Pro on a typical 3:1 input/output mix.
GPT-5.5 Pro vs GPT-6 Astra Pro: which has a bigger context window?
GPT-5.5 Pro: 1,050,000 tokens. GPT-6 Astra Pro: 1,050,000 tokens.
How much would 1 million requests cost?
At 2,000 input + 500 output tokens per request: GPT-5.5 Pro ≈ $150,000, GPT-6 Astra Pro ≈ $45,000.
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