Kimi K3 vs Claude Opus 4.8: Benchmarks, Price, Verdict

Short summary

Kimi K3 and Claude Opus 4.8 are statistically tied on graduate-level reasoning (GPQA Diamond) and aggregate intelligence benchmarks, but K3 costs 40% less per token. K3 leads in Arena Frontend Code and agentic terminal benchmarks, while Opus 4.8 retains an edge in SWE-bench Verified and ecosystem maturity for agent harnesses. The practical recommendation is to A/B test both on your own workload since switching requires a one-word model name change.

• •K3 and Opus 4.8 are statistically tied on GPQA Diamond and Artificial Analysis Intelligence Index
• •K3 is 40% cheaper across input, cached input, and output tokens
• •K3's reasoning is always-on at max effort; Opus 4.8 offers configurable reasoning effort per request

Generated with AI, which can make mistakes.