Gemini 1.5 Pro vs Gemini 2.5 Pro

Gemini 1.5 Pro vs Gemini 2.5 Pro: Gemini 1.5 Pro is cheaper by 50% on average. Gemini 1.5 Pro from Google Vertex AI (2,097,152-token context, tool calls) vs. Gemini 2.5 Pro 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
$1,179/mo
Input $1.25/M · Output $10.00/M
At this workload, Gemini 1.5 Pro is 26% cheaper than Gemini 2.5 Pro — a savings of $304/month ($3,653/year).
Production recipe — Agent Command Center
strategy: cost-optimized
primary:
  model: gemini-1-5-pro
  provider: vertex-ai
fallback:
  model: gemini-2-5-pro
  provider: vertex-ai
shadow: { sample_rate: 0.05 }   # mirror 5% of traffic to compare quality live
Gemini 1.5 Pro Gemini 2.5 Pro
Input price $1.25/M $1.25/M
Output price $5.00/M $10.00/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
~50% cheaper than Gemini 2.5 Pro
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 2.5 Pro
1,448
MATH-500math
Gemini 1.5 Pro
Gemini 2.5 Pro
93.7%
HumanEvalcode
Gemini 1.5 Pro
Gemini 2.5 Pro
93.6%
AIME 2025math
Gemini 1.5 Pro
Gemini 2.5 Pro
86.7%
MMLU-Proreasoning
Gemini 1.5 Pro
Gemini 2.5 Pro
86.7%
MMLUgeneral
Gemini 1.5 Pro
85.9%
Gemini 2.5 Pro
GPQA Diamondreasoning
Gemini 1.5 Pro
Gemini 2.5 Pro
84.0%
MMMUmultimodal
Gemini 1.5 Pro
62.2%
Gemini 2.5 Pro
79.6%
BFCL v3agent
Gemini 1.5 Pro
Gemini 2.5 Pro
76.0%
Aider Polyglotcode
Gemini 1.5 Pro
Gemini 2.5 Pro
73.3%
LiveCodeBenchcode
Gemini 1.5 Pro
Gemini 2.5 Pro
69.0%
MATHmath
Gemini 1.5 Pro
67.7%
Gemini 2.5 Pro
SWE-bench Verifiedagent
Gemini 1.5 Pro
Gemini 2.5 Pro
63.8%
GPQAreasoning
Gemini 1.5 Pro
46.2%
Gemini 2.5 Pro
Humanity's Last Examreasoning
Gemini 1.5 Pro
Gemini 2.5 Pro
18.8%