LLM Comparison
Grok 4 Fast vs Grok 4.20
Side-by-side specs, pricing & capabilities · Updated April 2026
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2/6 modelsSame tier:
| Organization | ||
| OpenTools Score | 77 19.3 | |
| Family | Grok | Grok |
| Status | Current | Current |
| Release Date | Sep 2025 | Mar 2026 |
| Context Window | 2.0M tokens | 2.0M tokens |
| Input Price | $0.20/M tokens | $2.00/M tokens |
| Output Price | $0.50/M tokens | $6.00/M tokens |
| Pricing Notes | Cache read: $0.0500/M tokens | Cache read: $0.2000/M tokens |
| Capabilities | textvisioncode | textvisioncode |
| Max Output | 30K tokens | — |
| API Identifier | x-ai/grok-4-fast | x-ai/grok-4.20 |
| View Grok 4 Fast | View Grok 4.20 |
Cost Calculator
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| Model | Input | Output | Total / mo | vs Best |
|---|---|---|---|---|
| Grok 4 FastCheapest | $0.20 | $0.25 | $0.45 | — |
| Grok 4.20 | $2.00 | $3.00 | $5.00 | +1011% |
xAI
Grok 4 Fast
Grok 4 Fast is a multimodal llm from xAI. Supports up to 2,000,000 token context window. Available from $0.20/M input tokens.
xAI
Grok 4.20
Grok 4.20 is a multimodal llm from xAI. Supports up to 2,000,000 token context window. Available from $2.00/M input tokens.
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