Grok 4.20 vs Grok 4.1 Fast
Pricing, context window, and benchmark comparison · Last updated April 2026
Grok 4.1 Fast is cheaper than Grok 4.20 at $0.20/1M/1M vs $2.00/1M/1M input tokens — a 10.0x cost difference. Grok 4.20 scores higher on quality benchmarks (ELO 1380). Choose Grok 4.1 Fast for cost-sensitive workloads; choose Grok 4.20 for maximum quality.
Which is cheaper: Grok 4.20 or Grok 4.1 Fast?
Grok 4.1 Fast is the cheaper option at $0.20/1M per 1M input tokens, compared to $2.00/1M for Grok 4.20. That is a 10.0x cost difference on input tokens. Output pricing follows a similar pattern: Grok 4.20 charges $6.00/1M/1M vs $0.50/1M/1M for Grok 4.1 Fast.
Which has better quality: Grok 4.20 or Grok 4.1 Fast?
Based on LMSYS Chatbot Arena rankings, Grok 4.20 achieves a higher ELO score (1380 vs 1305), suggesting stronger performance on open-ended tasks. Grok 4.20 excels at 2m token context window — tied for largest available. Grok 4.1 Fast is known for 2m token context at $0.20/$0.50 per 1m — unbeatable for long context.
Which should you choose: Grok 4.20 or Grok 4.1 Fast?
- → 2M token context window — tied for largest available
- → Real-time X (Twitter) data access
- → Strong reasoning and multi-agent variants
- → 2M token context at $0.20/$0.50 per 1M — unbeatable for long context
- → Very fast inference
- → Real-time X data access
Frequently Asked Questions
Which is cheaper: Grok 4.20 or Grok 4.1 Fast?
Grok 4.1 Fast is cheaper at $0.20/1M per 1M input tokens, making it 10.0x more affordable.
Which has better quality: Grok 4.20 or Grok 4.1 Fast?
Grok 4.20 scores higher on the LMSYS Chatbot Arena with an ELO of 1380, suggesting better overall quality for most tasks.
Which has a larger context window: Grok 4.20 or Grok 4.1 Fast?
Both Grok 4.20 and Grok 4.1 Fast have the same context window.
Should I choose Grok 4.20 or Grok 4.1 Fast?
Choose Grok 4.1 Fast if cost is the priority. Choose Grok 4.20 if benchmark quality is most important. Consider your specific use case: Grok 4.20 is best for reasoning and research, while Grok 4.1 Fast excels at long-context and low-cost.
Is Grok 4.20 or Grok 4.1 Fast open source?
Grok 4.20 is proprietary. Grok 4.1 Fast is proprietary.