Gemini 1.5 Pro vs Gemini 3.1 Pro preview
Gemini 1.5 Pro vs Gemini 3.1 Pro preview: Gemini 1.5 Pro is cheaper by 58% on average. Gemini 1.5 Pro from Google Vertex AI (2,097,152-token context, tool calls) vs. Gemini 3.1 Pro preview from Google Vertex AI (1,048,576-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
065,536
5,000
01,000,000
At this workload, Gemini 1.5 Pro is 47% cheaper than Gemini 3.1 Pro preview — a savings of $769/month ($9,223/year).
Production recipe — Agent Command Center
strategy: cost-optimized
primary:
model: gemini-1-5-pro
provider: vertex-ai
fallback:
model: gemini-3-1-pro-preview
provider: vertex-ai
shadow: { sample_rate: 0.05 } # mirror 5% of traffic to compare quality live| Gemini 1.5 Pro | Gemini 3.1 Pro preview | |
|---|---|---|
| Input price | $1.25/M | $2.00/M |
| Output price | $5.00/M | $12.00/M |
| Context window | 2,097,152 | 1,048,576 |
| Max output | 8,192 | 65,536 |
| Function calling | ✓ | ✓ |
| Vision | ✓ | ✓ |
| Audio input | — | ✓ |
| Reasoning | — | ✓ |
| Prompt caching | — | ✓ |
| Structured output | ✓ | ✓ |
| Pricing verified | May 7, 2026 | May 12, 2026 |
Benchmark comparison
Side-by-side public benchmark scores. Greener bar = winner.