Gemini 3.1 Pro preview vs Grok 3
Gemini 3.1 Pro preview vs Grok 3: Gemini 3.1 Pro preview is cheaper by 33% on average. Gemini 3.1 Pro preview from Google Vertex AI (1,048,576-token context, reasoning, tool calls) vs. Grok 3 from xAI (131,072-token context, 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
01,048,576
400
0131,072
5,000
01,000,000
At this workload, Gemini 3.1 Pro preview is 28% cheaper than Grok 3 — a savings of $639/month ($7,670/year).
Production recipe — Agent Command Center
strategy: cost-optimized
primary:
model: gemini-3-1-pro-preview
provider: vertex-ai
fallback:
model: grok-3
provider: xai
shadow: { sample_rate: 0.05 } # mirror 5% of traffic to compare quality live| Gemini 3.1 Pro preview | Grok 3 | |
|---|---|---|
| Input price | $2.00/M | $3.00/M |
| Output price | $12.00/M | $15.00/M |
| Context window | 1,048,576 | 131,072 |
| Max output | 65,536 | 131,072 |
| 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.
Chatbot Arena ELOgeneral
Gemini 3.1 Pro preview
1,492
Grok 3
1,402
GPQA Diamondreasoning⚠ different settings
Gemini 3.1 Pro preview
94.3%
Grok 3
75.4%