Claude Sonnet 4 vs Kimi K3
Detailed pricing comparison and cost analysis.
Updated September 2026
Cost Simulator
| Feature | Claude Sonnet 4 | Kimi K3 |
|---|---|---|
| Provider | Anthropic | Moonshot AI |
| Input Price (1M) | $3.00 | $3.00 |
| Output Price (1M) | $15.00 | $15.00 |
| Context Window | 200,000 | 1,000,000 |
Verdict
Claude Sonnet 4 costs $3.00 per 1M input tokens and $15.00 per 1M output tokens. Kimi K3 costs $3.00 per 1M input tokens and $15.00 per 1M output tokens. Claude Sonnet 4 and Kimi K3 have identical input token pricing. For output tokens, Claude Sonnet 4 is the more affordable option at $15.00/1M vs $15.00.
On context window, Kimi K3 supports 1,000,000 tokens — meaning it can fit more conversation history, documents, or code in a single request. This matters for RAG pipelines, long document analysis, and agentic workflows where context builds up over many turns.
When to choose Claude Sonnet 4
- ✓ You are already integrated with Anthropic
When to choose Kimi K3
- ✓ You need a larger context window (1,000,000 tokens)
- ✓ You are already integrated with Moonshot AI
Use the calculator above to simulate your specific workload and find the exact break-even point. For most applications, the cheapest model is the one that minimises your total monthly bill given your input-to-output token ratio.
Frequently Asked Questions
Is Claude Sonnet 4 cheaper than Kimi K3? ▼
Claude Sonnet 4 and Kimi K3 have identical input token pricing at $3.00/1M tokens.
What is the context window of Claude Sonnet 4 vs Kimi K3? ▼
Claude Sonnet 4 has a 200,000-token context window. Kimi K3 has a 1,000,000-token context window. Kimi K3 supports the larger context, suitable for longer documents and agentic workflows.
Which model is better: Claude Sonnet 4 or Kimi K3? ▼
The best choice depends on your use case. For cost efficiency on input tokens, Claude Sonnet 4 is the cheaper option. For maximum context length, Kimi K3 supports 1,000,000 tokens. Use the comparison table above to find the right fit for your workload.