GPT-6 Astra vs GPT-5.6 Sol vs GPT-5.5
Pick two to four models to compare benchmark scores, prices, context windows and speed. The link updates as you pick, so you can share the exact comparison.
Cheapest blended
GPT-5.6 Sol
$8.00 / 1M tokens
Largest context
GPT-6 AstraGPT-5.6 SolGPT-5.5
Tie at 1.05M tokens
Fastest output
GPT-5.5
86 tokens/s
Top on DeepSWE v1.1
GPT-6 Astra
74.1%
Specifications
| Spec | GPT-6 AstraOpenAI | GPT-5.6 SolOpenAI | GPT-5.5OpenAI |
|---|---|---|---|
| Provider | OpenAI | OpenAI | OpenAI |
| Released | 3 Sep 2026 | 9 Jul 2026 | 24 Apr 2026 |
| Licence | Proprietary | Proprietary | Proprietary |
| Context window | 1.05M tokens | 1.05M tokens | 1.05M tokens |
| Max output | 128K tokens | 128K tokens | 128K tokens |
| Input / 1M | $10.00* | $4.00* | $5.00* |
| Output / 1M | $50.00 | $20.00 | $30.00 |
| Cached input / 1M | $1.00 | $0.40 | $0.50 |
| Speed | 51 tokens/s | 79 tokens/s | 86 tokens/s |
| Input types | text, image | text, image | text, image |
| Best for | CodingAgentsReasoningResearch | CodingAgentsReasoning | CodingAgents |
* GPT-6 Astra: Cache writes are 1.25x input; cache reads 0.1x; 30-minute minimum cache life. Batch and Flex: $5 in / $25 out. Fast mode (formerly Priority): 2x, $20 / $100. Ultrafast (Responses API, service_tier "ultrafast", Astra only): $60 in / $6 cached / $75 cache write / $300 out. Data residency endpoints +10%.
* GPT-5.6 Sol: Promotional price since 21 Aug 2026 (launch price was $5 in / $30 out). OpenAI says it is 'available at least through November 21, 2026'. Batch and Flex: $2 / $10. Fast mode: $8 / $40. Cache writes 1.25x input; 30-minute minimum cache life. The alias gpt-5.6 routes to this model. Data residency +10%.
* GPT-5.5: There is no separate cache-write charge (pre-GPT-5.6 models). Batch and Flex: $2.50 / $15. Fast mode: 2.5x, $12.50 / $75. Snapshot gpt-5.5-2026-04-23. GPT-5.5 Pro (gpt-5.5-pro) costs $30 / $180. Data residency +10%.
Benchmark scores
Officially reported scores only. A model with no published score on a benchmark shows a line, not a zero.
Price per 1M tokens
Context window and speed
Notes
- GPT-6 Astra
- OpenAI's most capable model, for the hardest end-to-end work: complex reasoning, coding, computer use, research and document creation.
- GPT-5.6 Sol
- Flagship of the GPT-5.6 family, for complex professional work, coding and long-horizon agentic tasks. It adds max reasoning effort and Pro mode.
- GPT-5.5
- A frontier model for coding and complex professional work, the flagship before GPT-5.6.
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