Grok 4.5 vs Kimi K3
Detailed pricing comparison and cost analysis.
Updated September 2026
Cost Simulator
| Feature | Grok 4.5 | Kimi K3 |
|---|---|---|
| Provider | xAI | Moonshot AI |
| Input Price (1M) | $2.00 | $3.00 |
| Output Price (1M) | $6.00 | $15.00 |
| Context Window | 500,000 | 1,000,000 |
Verdict
Grok 4.5 costs $2.00 per 1M input tokens and $6.00 per 1M output tokens. Kimi K3 costs $3.00 per 1M input tokens and $15.00 per 1M output tokens. Grok 4.5 is 33% cheaper on input tokens than Kimi K3. For output tokens, Grok 4.5 is the more affordable option at $6.00/1M vs $15.00.
On context window, Kimi K3 supports 1,000,000 tokens — meaning it can fit more conversation history, documents, or code in a single request. This matters for RAG pipelines, long document analysis, and agentic workflows where context builds up over many turns.
When to choose Grok 4.5
- ✓ You need the lowest input token cost ($ 2.00/1M)
- ✓ Your workload is output-heavy — Grok 4.5 generates text cheaper
- ✓ You are already integrated with xAI
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 Grok 4.5 cheaper than Kimi K3? ▼
Grok 4.5 is cheaper on input tokens at $2.00/1M vs $3.00/1M for Kimi K3 — a 33% saving.
What is the context window of Grok 4.5 vs Kimi K3? ▼
Grok 4.5 has a 500,000-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: Grok 4.5 or Kimi K3? ▼
The best choice depends on your use case. For cost efficiency on input tokens, Grok 4.5 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.