Grok-3 vs Grok 4 Fast: Specs & Benchmark Comparison
| Characteristic | Grok-3 | Grok 4 Fast |
|---|---|---|
| Company | xAI | xAI |
| Release Date | February 16, 2025 | August 27, 2025 |
| Parameters | — | — |
| Multimodal | Yes | Yes |
| Context (input) | 128K | 2.0M |
| Context (output) | 8K | 30K |
| Input Price / 1M | $3.00 | $0.20 |
| Output Price / 1M | $15.00 | $0.50 |
| Average Score | 0.8 | 0.8 |
| Benchmarks | ||
| GPQA | 0.8 | 0.9 |
| LiveCodeBench | 0.8 | 0.8 |
Visual Benchmark Comparison
Grok-3
Grok 4 Fast
GPQA0.8 vs 0.9
0.8
0.9
LiveCodeBench0.8 vs 0.8
0.8
0.8
Verdict
Grok 4 Fast leads in 3 out of 4 comparison categories.
Overall Performance
Both models show comparable average scores: Grok-3 — 0.8, Grok 4 Fast — 0.8.
API Cost
Grok 4 Fast is 25.7x cheaper: input $0.20/1M vs $3.00/1M tokens.
Context Window
Grok 4 Fast supports a larger context: 2M vs 128K tokens.
Recency
Grok 4 Fast is newer: released 8/27/2025 vs 2/16/2025.
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Frequently Asked Questions
Which is better for coding — Grok-3 or Grok 4 Fast?
Direct comparison on the SWE-Bench benchmark is not available. We recommend reviewing other metrics on the comparison page.
Which model is cheaper — Grok-3 or Grok 4 Fast?
Grok 4 Fast is cheaper for input: $0.20 per 1M tokens vs $3.00.
Which has a larger context window — Grok-3 or Grok 4 Fast?
Grok 4 Fast supports a larger context: 2,000,000 tokens vs 128,000.
The Grok-3 and Grok 4 Fast comparison is updated for 2026. Data includes benchmark results, API pricing, context window size and other specifications. For more detailed information, visit the Grok-3 or Grok 4 Fast page. See also the complete list of AI model comparisons.