Gemini 3.1 Pro preview vs GPT-4o
Gemini 3.1 Pro preview vs GPT-4o: GPT-4o is cheaper by 20% on average. Gemini 3.1 Pro preview from Google Vertex AI (1,048,576-token context, reasoning, tool calls) vs. GPT-4o from Azure OpenAI (128,000-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
065,536
5,000
01,000,000
At this workload, Gemini 3.1 Pro preview is 6% cheaper than GPT-4o — a savings of $107/month ($1,278/year).
Crossover: Gemini 3.1 Pro preview is cheaper when output/input ≤ 0.25 (input-heavy workloads — RAG, retrieval). GPT-4o wins above (long-form generation).
Current workload ratio: 0.13 (400/3000)
Production recipe — Agent Command Center
strategy: cost-optimized
primary:
model: gemini-3-1-pro-preview
provider: vertex-ai
fallback:
model: gpt-4o
provider: azure-openai
shadow: { sample_rate: 0.05 } # mirror 5% of traffic to compare quality live| Gemini 3.1 Pro preview | GPT-4o | |
|---|---|---|
| Input price | $2.00/M | $2.50/M |
| Output price | $12.00/M | $10.00/M |
| Context window | 1,048,576 | 128,000 |
| Max output | 65,536 | 16,384 |
| 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
GPT-4o
1,265