GPT-6 Astra vs Kimi K3: Specs & Benchmark Comparison
GPT-6 Astra is developed by OpenAI, while Kimi K3 comes from Moonshot AI. Kimi K3 was released in July 2026, and GPT-6 Astra followed 2 months later in September 2026. Kimi K3 has a published size of about 2.8 trillion parameters; OpenAI has not disclosed the parameter count of GPT-6 Astra.
The two models share 4 published benchmarks. GPT-6 Astra leads on 4 of them. The widest gaps are on AutomationBench, where GPT-6 Astra scores 41.4% against 30.8%; DeepSWE 1.1, where GPT-6 Astra scores 74.1% against 69.0%. Averaged across everything we track, GPT-6 Astra sits at 74.4% and Kimi K3 at 67.8%.
Kimi K3 is the cheaper API at $3 per million input tokens and $15 per million output tokens, roughly 3 times cheaper than GPT-6 Astra at $10 and $50. Both accept a context window of about 1M tokens. Both accept text and images as input.
| Characteristic | GPT-6 Astra | Kimi K3 |
|---|---|---|
| Company | OpenAI | Moonshot AI |
| Release Date | September 4, 2026 | July 16, 2026 |
| Parameters | — | 2.8T |
| Multimodal | Yes | Yes |
| Context (input) | 1.1M | 1.0M |
| Context (output) | 128K | 1.0M |
| Input Price / 1M | $10.00 | $3.00 |
| Output Price / 1M | $50.00 | $15.00 |
| Average Score | 74.4% | 67.8% |
| Benchmarks | ||
| AutomationBench | 41.4% | 30.8% |
| DeepSWE 1.1 | 74.1% | 69.0% |
| GPQA Diamond | 96.0% | 94.0% |
| BrowseComp | 91.5% | 91.2% |
Visual Benchmark Comparison
Verdict
GPT-6 Astra leads in 2 out of 4 comparison categories.
Both models show comparable average scores: GPT-6 Astra — 0.7, Kimi K3 — 0.7.
Kimi K3 is 3.3x cheaper: input $3.00/1M vs $10.00/1M tokens.
GPT-6 Astra supports a larger context: 1M vs 1M tokens.
GPT-6 Astra is newer: released 9/4/2026 vs 7/16/2026.
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Frequently Asked Questions
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The GPT-6 Astra and Kimi K3 comparison is updated for 2026. Data includes benchmark results, API pricing, context window size and other specifications. For more detailed information, visit the GPT-6 Astra or Kimi K3 page. See also the complete list of AI model comparisons.