Claude Opus 4.8 vs Kimi K3

Claude Opus 4.8 and Kimi K3 are both current production-tier models. Kimi K3 is meaningfully cheaper at $3 / $15 per 1M. Claude Opus 4.8 leads on reasoning, instruction following, tool use.

Specs side by side

Metric
Anthropic
Claude Opus 4.8
Z.ai
Kimi K3
Input price (per 1M)$5$3
Output price (per 1M)$25$15
Context window1M tokens1.0M tokens
Speed tierslowbalanced
Open weightsNoNo
EU regionYesNo
Free tierNoNo
Prompt cachingYesYes
Vision inputYesYes
Extended thinkingYesYes

When to choose each

Anthropic

Choose Claude Opus 4.8 if…

  • EU data residency is required
  • HIPAA eligibility is required
  • Reasoning is central to your workload
  • Instruction following is central to your workload
Z.ai

Choose Kimi K3 if…

  • Kimi K3 is in the same tier as Claude Opus 4.8 — pick by provider preference or API ecosystem

Benchmark delta

Claude Opus 4.8 leads on

  • Reasoning
  • Instruction following
  • Tool use

Kimi K3 leads on

Kimi K3 has no meaningful benchmark lead in this pair.

FAQ — Claude Opus 4.8 vs Kimi K3

Claude Opus 4.8 vs Kimi K3 — which is better?

Claude Opus 4.8 and Kimi K3 are both current production-tier models. Kimi K3 is meaningfully cheaper at $3 / $15 per 1M. Claude Opus 4.8 leads on reasoning, instruction following, tool use. The right pick depends on your use case — see "When to choose each" above for a data-driven decision.

How does Claude Opus 4.8 pricing compare to Kimi K3?

Claude Opus 4.8 costs $5 / $25 per 1M vs Kimi K3 at $3 / $15 per 1M. Kimi K3 is cheaper on output tokens by roughly 67%. Both support prompt caching, which reduces effective cost by 80-90% on repeat system prompts.

Does Claude Opus 4.8 or Kimi K3 have the bigger context window?

Kimi K3 has a 1.0M-token context window — 1× the 1M context of Claude Opus 4.8. Enough for entire codebases, books, or multi-document RAG.

Is there a free tier for Claude Opus 4.8 or Kimi K3?

Claude Opus 4.8: no — Free via Claude.ai web chat; API requires paid credits. Kimi K3: no — No free API tier; kimi.com web chat is free with limits.

Which is better for coding — Claude Opus 4.8 or Kimi K3?

Claude Opus 4.8 leads on coding benchmarks (Claude Opus 4.8: 97/100, Kimi K3: 95/100). For production coding agents also weigh tool-use performance — Claude Opus 4.8 scores 96, Kimi K3 scores 90.