AI model comparison
GPT-6 Astra vs Kimi K3
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
Moonshot AI
Kimi K3
Kimi K3 is a 2.8T parameter open-weight multimodal reasoning model from Moonshot AI.
- Input / 1M
- $0.90
- Output / 1M
- $14
- Context
- 1.05M
At a glance
Quick verdict
How the two models stack up on the things people ask about most.
Lower price
Kimi K3
5.1x cheaper for a typical chat
Higher intelligence score
GPT-6 Astra
52.7 vs 43.6 on Artificial Analysis
Larger context window
GPT-6 Astra
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 Astra52.7Coding index
GPT-6 Astra76.9Agentic index
GPT-6 Astra51Pricing
GPT-6 Astra vs Kimi K3 API pricing
Per-token API rates. Cheaper option highlighted.
| Metric | GPT-6 Astra | |
|---|---|---|
| Input tokensPer 1M tokens | $10 | $0.90 |
| Output tokensPer 1M tokens | $50 | $14 |
| Cached input (read)Per 1M tokens | $1 | $0.60 |
| Cache writePer 1M tokens | $12.50 | Not available |
| Long-context pricingPer 1M tokens, for very long prompts | $20 in / $75 out above 272K | Same rate at any length |
| Web searchPer request | $0.01 | Not available |
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$45Coding task
30K in, 4K out
GPT-6 Astra$500$230 cachedLong document summary
150K in, 2K out
GPT-6 Astra$1600$250 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 | |
|---|---|---|
| Context window | 1.05M tokens | 1.05M tokens |
| Max output | 128K tokens | 944K tokens |
| Input types | File, Image, Text | Image, Text, Video |
| Output types | Text | Text |
| Reasoning effort levels | Max, Extra high, High, Medium, Low | Max, High, Low |
| Default reasoning effort | Medium | Max |
| Release date | September 4, 2026 | July 16, 2026 |
Features
Supported features
API features available for each model.
| Metric | GPT-6 Astra | |
|---|---|---|
| Tool calling | Supported | Supported |
| Structured outputs | Supported | Supported |
| JSON mode | Supported | Supported |
| Reasoning | Supported | Supported |
| Temperature | Not supported | Supported |
| Stop sequences | Not supported | Supported |
| Deterministic seed | Supported | Supported |
| Verbosity control | Supported | Not 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 GPT-5.6 Sol
- GPT-6 Astra vs Grok 4.7
- GPT-6 Astra vs GLM 5.3
- 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
- Kimi K3 vs Claude Opus 5.5
- Kimi K3 vs Claude Fable 5.1
- Kimi K3 vs GPT-6.1 Sol
- Kimi K3 vs Claude Opus 5
- Kimi K3 vs Claude Fable 5
- Kimi K3 vs GLM 5.3
- Kimi K3 vs GPT-6 Sol
- Kimi K3 vs GPT-5.6 Sol
- Kimi K3 vs Gemini 3.8 Flash
- Kimi K3 vs Grok 4.7
- Kimi K3 vs Qwen3.8 Max (0902)
- Kimi K3 vs Grok 4.6
- Kimi K3 vs Claude Haiku 5.5
- Kimi K3 vs GPT-5.6 Terra
- Kimi K3 vs Claude Opus 4.8
- Kimi K3 vs Ling 3.1 Flash
- Kimi K3 vs Claude Opus 4.7
- Kimi K3 vs Qwen3.8 2.4T A95B
- Kimi K3 vs GPT-5.4
- Kimi K3 vs Claude Sonnet 5
- Kimi K3 vs GPT-5.5
Our take
Kimi K3 is 5.1x cheaper for a typical chat. GPT-6 Astra scores higher on the Artificial Analysis Intelligence Index (52.7 vs 43.6). GPT-6 Astra has the larger context window (1.05M vs 1.05M tokens). 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 Kimi K3 cheaper?
Kimi K3 is cheaper for a typical chat (2K input tokens and 500 output tokens). Kimi K3 costs $0.90 per 1M input tokens and $14 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 Kimi K3?
GPT-6 Astra supports up to 1.05M tokens of context, compared with 1.05M for Kimi K3.
Is GPT-6 Astra smarter than Kimi K3?
On the Artificial Analysis Intelligence Index, GPT-6 Astra scores 52.7 and Kimi K3 scores 43.6, 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 Kimi K3 at the same time?
Yes. Shortcut Chat sends one prompt to multiple models at once, so you can see GPT-6 Astra and Kimi K3 answer side by side and keep the better response.
Why choose? Ask both.
Send one prompt to GPT-6 Astra and Kimi K3 at the same time. Compare the answers side by side and keep the best one.