AI model comparison
GPT-6 Astra vs GPT-5.6 Sol
Pricing, context window, benchmarks, and features compared side by side. Or skip the guesswork and send one prompt to both.
OpenAI
GPT-6 Astra
GPT-6 Astra is OpenAI's flagship model for demanding end-to-end work.
- Input / 1M
- $10
- Output / 1M
- $50
- Context
- 1.05M
OpenAI
GPT-5.6 Sol
GPT-5.6 Sol is the flagship model in OpenAI's GPT-5.6 series.
- Input / 1M
- $2
- Output / 1M
- $10
- Context
- 1.05M
At a glance
Quick verdict
How the two models stack up on the things people ask about most.
Lower price
GPT-5.6 Sol
5.0x cheaper for a typical chat
Higher intelligence score
GPT-6 Astra
52.7 vs 47 on Artificial Analysis
Larger context window
Tie
1.05M vs 1.05M tokens
Newer release
GPT-6 Astra
Released September 4, 2026
Benchmarks
Benchmark scores
Independent scores from Artificial Analysis. Higher is better.
Intelligence index
GPT-6 Astra52.7GPT-5.6 Sol47Coding index
GPT-6 Astra76.9GPT-5.6 Sol77.4Agentic index
GPT-6 Astra51GPT-5.6 Sol50.2Pricing
GPT-6 Astra vs GPT-5.6 Sol API pricing
Per-token API rates. Cheaper option highlighted.
| Metric | GPT-6 Astra | GPT-5.6 Sol |
|---|---|---|
| Input tokensPer 1M tokens | $10 | $2 |
| Output tokensPer 1M tokens | $50 | $10 |
| Cached input (read)Per 1M tokens | $1 | $0.20 |
| Cache writePer 1M tokens | $12.50 | $2.50 |
| Long-context pricingPer 1M tokens, for very long prompts | $20 in / $75 out above 272K | $4 in / $15 out above 272K |
| Web searchPer request | $0.01 | $0.01 |
What it costs in practice
Estimated cost per 1,000 requests at standard rates. Coding and long-document figures also show the cost when the input is already cached.
Chat message
2K in, 500 out
GPT-6 Astra$45GPT-5.6 Sol$9Coding task
30K in, 4K out
GPT-6 Astra$500$230 cachedGPT-5.6 Sol$100$46 cachedLong document summary
150K in, 2K out
GPT-6 Astra$1600$250 cachedGPT-5.6 Sol$320$50 cachedSpecs
Context window and capabilities
How much each model can read, how much it can write, and what it accepts as input.
| Metric | GPT-6 Astra | GPT-5.6 Sol |
|---|---|---|
| Context window | 1.05M tokens | 1.05M tokens |
| Max output | 128K tokens | 128K tokens |
| Input types | File, Image, Text | File, Image, Text |
| Output types | Text | Text |
| Reasoning effort levels | Max, Extra high, High, Medium, Low | Max, Extra high, High, Medium, Low, None |
| Default reasoning effort | Medium | Medium |
| Release date | September 4, 2026 | July 9, 2026 |
Features
Supported features
API features available for each model.
| Metric | GPT-6 Astra | GPT-5.6 Sol |
|---|---|---|
| Tool calling | Supported | Supported |
| Structured outputs | Supported | Supported |
| JSON mode | Supported | Supported |
| Reasoning | Supported | Supported |
| Temperature | Not supported | Not supported |
| Stop sequences | Not supported | Not supported |
| Deterministic seed | Supported | Supported |
| Verbosity control | Supported | Supported |
Keep exploring
More on these models
Other head-to-heads, the full model page, and the alternatives list for each model.
GPT-6 AstraView full model details- GPT-6 Astra vs Claude Opus 5.5
- GPT-6 Astra vs Claude Sonnet 5.5
- GPT-6 Astra vs Claude Fable 5.1
- GPT-6 Astra vs GPT-6.1 Sol
- GPT-6 Astra vs Claude Opus 5
- GPT-6 Astra vs Claude Fable 5
- GPT-6 Astra vs Muse Spark 1.3
- GPT-6 Astra vs GPT-6 Sol
- GPT-6 Astra vs Grok 4.7
- GPT-6 Astra vs GLM 5.3
- GPT-6 Astra vs Kimi K3
- GPT-6 Astra vs GLM 5.3 Flash
- GPT-6 Astra vs Gemini 3.8 Flash
- GPT-6 Astra vs DeepSeek V4.1 Flash
- GPT-6 Astra vs MiMo-V2.6-Flash
- GPT-6 Astra vs Hy4 preview
- GPT-6 Astra vs GPT-6 Luna
- GPT-6 Astra vs DeepSeek V4 Flash 0731
- GPT-6 Astra vs Gemini 3.1 Pro Preview
GPT-5.6 SolView full model details- GPT-5.6 Sol vs Claude Opus 5.5
- GPT-5.6 Sol vs Claude Sonnet 5.5
- GPT-5.6 Sol vs Claude Fable 5.1
- GPT-5.6 Sol vs GPT-6.1 Sol
- GPT-5.6 Sol vs Claude Opus 5
- GPT-5.6 Sol vs Claude Fable 5
- GPT-5.6 Sol vs Muse Spark 1.3
- GPT-5.6 Sol vs GPT-6 Sol
- GPT-5.6 Sol vs Grok 4.7
- GPT-5.6 Sol vs MiMo-V2.6-Pro
- GPT-5.6 Sol vs Qwen3.8 Max (0902)
- GPT-5.6 Sol vs GLM 5.3
- GPT-5.6 Sol vs Grok 4.6
- GPT-5.6 Sol vs Kimi K3
- GPT-5.6 Sol vs GPT-5.6 Terra
- GPT-5.6 Sol vs GPT-5.4
Our take
GPT-5.6 Sol is 5.0x cheaper for a typical chat. GPT-6 Astra scores higher on the Artificial Analysis Intelligence Index (52.7 vs 47). The right pick depends on your workload, so the quickest way to settle it is to send the same prompt to both and compare.
FAQ
Frequently asked questions
Is GPT-6 Astra or GPT-5.6 Sol cheaper?
GPT-5.6 Sol is cheaper for a typical chat (2K input tokens and 500 output tokens). GPT-5.6 Sol costs $2 per 1M input tokens and $10 per 1M output tokens, while GPT-6 Astra costs $10 per 1M input tokens and $50 per 1M output tokens.
Which has a bigger context window, GPT-6 Astra or GPT-5.6 Sol?
GPT-6 Astra supports up to 1.05M tokens of context, compared with 1.05M for GPT-5.6 Sol.
Is GPT-6 Astra smarter than GPT-5.6 Sol?
On the Artificial Analysis Intelligence Index, GPT-6 Astra scores 52.7 and GPT-5.6 Sol scores 47, putting GPT-6 Astra ahead. Benchmarks don't capture everything, so the best test is running your own prompts through both.
Can I use GPT-6 Astra and GPT-5.6 Sol at the same time?
Yes. Shortcut Chat sends one prompt to multiple models at once, so you can see GPT-6 Astra and GPT-5.6 Sol answer side by side and keep the better response.
Why choose? Ask both.
Send one prompt to GPT-6 Astra and GPT-5.6 Sol at the same time. Compare the answers side by side and keep the best one.