GPT-6 Astra vs Kimi K3
GPT-6 Astra scores higher on the Models at Work leaderboard (86 vs 60 out of 100). Kimi K3 is about 8.7× cheaper per blended million tokens ($2.31 vs $20, one figure an Artificial Analysis estimate). On Artificial Analysis' independent Intelligence Index, GPT-6 Astra leads 53 to 44.
| GPT-6 Astra · OpenAI | Kimi K3 · Moonshot | |
|---|---|---|
| Leaderboard rank | #2 | #11 |
| Score (0–100) | 86 | 60 |
| Tier | Frontier | Open weights |
| Price per 1M tokens | $10 in · $50 out | $2.31 blended (estimate) |
| Context window | 1M | Not verified |
| Open weights | No | Yes |
| Artificial Analysis Intelligence Index | 53 | 44 |
| Humanity's Last Exam, Diamond (Scale) | 60.6 | — |
| Humanity's Sixth Sense (Scale) | 53.6 | — |
| FrontierMath Erdős (Epoch) | 3% (2 of 68) | — |
| Arena text score | — | 1488 |
| Best for | Hard reasoning, Research-grade analysis, When cost is not the constraint | Self-hosting, Open-licence requirements, Arena-style chat quality |
Choose GPT-6 Astra if…
- you need hard reasoning
- you need research-grade analysis
- you need when cost is not the constraint
The reasoning heavyweight: leads the hardest exams and the cipher-cracking party tricks, and charges like it.
Caveats: Long-context pricing doubles above 272K input tokens. Speed is the lowest of the frontier set in Artificial Analysis' measurement.
Choose Kimi K3 if…
- you need self-hosting
- you need open-licence requirements
- you need arena-style chat quality
The highest-placed open-licence model on Arena, and the one most teams have not tried yet.
Caveats: Price is Artificial Analysis' blended figure, not a vendor list price; context not verified from a primary source.
What practitioners say
GPT-6 Astra: The launch drew the largest model thread of 2026 on Hacker News, and the stories that followed were about capability rather than cost: an Enigma message unsolved since 2005, a WWI cipher, a driving benchmark.
Questions people ask
Which is better, GPT-6 Astra or Kimi K3?
GPT-6 Astra scores higher on the Models at Work leaderboard (86 vs 60 out of 100). Kimi K3 is about 8.7× cheaper per blended million tokens ($2.31 vs $20, one figure an Artificial Analysis estimate). On Artificial Analysis' independent Intelligence Index, GPT-6 Astra leads 53 to 44.
When should I choose GPT-6 Astra over Kimi K3?
Choose GPT-6 Astra for hard reasoning, research-grade analysis, when cost is not the constraint. The reasoning heavyweight: leads the hardest exams and the cipher-cracking party tricks, and charges like it.
When should I choose Kimi K3 over GPT-6 Astra?
Choose Kimi K3 for self-hosting, open-licence requirements, arena-style chat quality. The highest-placed open-licence model on Arena, and the one most teams have not tried yet.
Which is cheaper, GPT-6 Astra or Kimi K3?
GPT-6 Astra costs $10 per million input tokens and $50 per million output tokens on OpenAI's list price (OpenAI API pricing, read Oct 10, 2026). Moonshot does not publish a simple list price for Kimi K3; Artificial Analysis estimates a blended $2.31 per million tokens (three input to one output).
Scores come from the Models at Work leaderboard: Score is 0 to 100: 50% independent evals normalised within this table, 20% price-performance, 15% practitioner sentiment from Signals and community threads, 15% operational fit (context, speed, availability, open weights). Models within three points are a tie in practice. Vendor-published figures are labelled as such and never counted as independent. Prices are vendor list prices where published; blended figures assume three input tokens per output token.