Gemini 1.5 Pro vs Gemini 3 Pro Preview

Gemini 1.5 Pro vs Gemini 3 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 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
065,535
5,000
01,000,000
Google Vertex AI
$875/mo
Input $1.25/M · Output $5.00/M
Google Vertex AI
$1,644/mo
Input $2.00/M · Output $12.00/M
At this workload, Gemini 1.5 Pro is 47% cheaper than Gemini 3 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-pro-preview
  provider: vertex-ai
shadow: { sample_rate: 0.05 }   # mirror 5% of traffic to compare quality live
Gemini 1.5 Pro Gemini 3 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 65,535
Function calling
Vision
Audio input
Reasoning
Prompt caching
Structured output
Pricing verified May 7, 2026 May 12, 2026
Cheaper option
~58% cheaper than Gemini 3 Pro Preview
Larger context
2,097,152 tokens
More capabilities
6 of 6 capability flags advertised

Benchmark comparison

Side-by-side public benchmark scores. Greener bar = winner.

Chatbot Arena ELOgeneral
Gemini 1.5 Pro
Gemini 3 Pro Preview
1,486
MMLUgeneral
Gemini 1.5 Pro
85.9%
Gemini 3 Pro Preview
MATHmath
Gemini 1.5 Pro
67.7%
Gemini 3 Pro Preview
MMMUmultimodal
Gemini 1.5 Pro
62.2%
Gemini 3 Pro Preview
GPQAreasoning
Gemini 1.5 Pro
46.2%
Gemini 3 Pro Preview