Gemini 3.5 Flash vs Grok 4.20 Beta
Detailed pricing comparison and cost analysis.
Updated September 2026
Cost Simulator
| Feature | Gemini 3.5 Flash | Grok 4.20 Beta |
|---|---|---|
| Provider | xAI | |
| Input Price (1M) | $1.50 | $1.25 |
| Output Price (1M) | $9.00 | $2.50 |
| Context Window | 1,000,000 | 1,000,000 |
Verdict
Gemini 3.5 Flash costs $1.50 per 1M input tokens and $9.00 per 1M output tokens. Grok 4.20 Beta costs $1.25 per 1M input tokens and $2.50 per 1M output tokens. Grok 4.20 Beta is 17% cheaper on input tokens than Gemini 3.5 Flash. For output tokens, Grok 4.20 Beta is the more affordable option at $2.50/1M vs $9.00.
On context window, Gemini 3.5 Flash supports 1,000,000 tokens — meaning it can fit more conversation history, documents, or code in a single request. This matters for RAG pipelines, long document analysis, and agentic workflows where context builds up over many turns.
When to choose Gemini 3.5 Flash
- ✓ You are already integrated with Google
When to choose Grok 4.20 Beta
- ✓ You need the lowest input token cost ($ 1.25/1M)
- ✓ Your workload is output-heavy — Grok 4.20 Beta generates text cheaper
- ✓ You are already integrated with xAI
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 Gemini 3.5 Flash cheaper than Grok 4.20 Beta? ▼
Grok 4.20 Beta is cheaper on input tokens at $1.25/1M vs $1.50/1M for Gemini 3.5 Flash — a 17% saving.
What is the context window of Gemini 3.5 Flash vs Grok 4.20 Beta? ▼
Gemini 3.5 Flash has a 1,000,000-token context window. Grok 4.20 Beta has a 1,000,000-token context window. Gemini 3.5 Flash supports the larger context, suitable for longer documents and agentic workflows.
Which model is better: Gemini 3.5 Flash or Grok 4.20 Beta? ▼
The best choice depends on your use case. For cost efficiency on input tokens, Grok 4.20 Beta is the cheaper option. For maximum context length, Gemini 3.5 Flash supports 1,000,000 tokens. Use the comparison table above to find the right fit for your workload.