Grok 3 vs Grok 4.1 Fast Reasoning
Grok 3 vs Grok 4.1 Fast Reasoning: Grok 4.1 Fast Reasoning is cheaper by 97% on average. Grok 3 from xAI (131,072-token context, tool calls) vs. Grok 4.1 Fast Reasoning from xAI (2,000,000-token context, reasoning, tool calls). Use Agent Command Center to A/B both in shadow mode and pick the winner per workload.
Side-by-side cost
Live workload comparison
Same workload run through both models. The cheaper one is highlighted.
3,000
02,000,000
400
0200,000
5,000
01,000,000
At this workload, Grok 4.1 Fast Reasoning is 95% cheaper than Grok 3 — a savings of $2,161/month ($25,933/year).
Production recipe — Agent Command Center
strategy: cost-optimized
primary:
model: grok-4-1-fast-reasoning
provider: xai
fallback:
model: grok-3
provider: xai
shadow: { sample_rate: 0.05 } # mirror 5% of traffic to compare quality live| Grok 3 | Grok 4.1 Fast Reasoning | |
|---|---|---|
| Input price | $3.00/M | $0.200/M |
| Output price | $15.00/M | $0.500/M |
| Context window | 131,072 | 2,000,000 |
| Max output | 131,072 | 2,000,000 |
| Function calling | ✓ | ✓ |
| Vision | — | ✓ |
| Audio input | — | ✓ |
| Reasoning | — | ✓ |
| Prompt caching | ✓ | ✓ |
| Structured output | — | ✓ |
| Pricing verified | May 12, 2026 | May 12, 2026 |
Benchmark comparison
Side-by-side public benchmark scores. Greener bar = winner.