GPT-6 Astra vs Kimi K3

GPT-6 Astra (OpenAI) and Kimi K3 (Moonshot AI) compared on price, context window, speed and independent benchmarks. GPT-6 Astra scores higher on the Artificial Analysis Intelligence Index (61.2 vs 59.7), while Kimi K3 is 3.3× cheaper on a blended basis. Pick GPT-6 Astra for the hardest tasks and Kimi K3 when cost dominates.

GPT-6 AstraKimi K3
ProviderOpenAIMoonshot AI
Input $/1M$10.0$3.00
Output $/1M$50.0$15.0
Blended $/1M (3:1)$20.0$6.00
Cached input $/1M$1.00$0.30
Context window1.1M1.0M
Knowledge cutoff2026-04
Licenseproprietaryopen weights
Speed (tok/s)38
Artificial Analysis Intelligence Index61.259.7
LMArena Elo1476
GPQA Diamond96.1%93.5%
SWE-bench Verified93.4%
Humanity's Last Exam54.7%46.9%
MMMU81.6%

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