Gemini 2.5 Pro Preview (May' 25) vs Gemini 2.5 Flash Preview (Sep '25) (Reasoning): The Ultimate Performance & Pricing Comparison

Deep dive into reasoning, benchmarks, and latency insights.

The Final Verdict in the Gemini 2.5 Pro Preview (May' 25) vs Gemini 2.5 Flash Preview (Sep '25) (Reasoning) Showdown

After a comprehensive analysis, Gemini 2.5 Pro Preview (May' 25) emerges as the superior choice for users prioritizing raw intelligence and reasoning. However, Gemini 2.5 Flash Preview (Sep '25) (Reasoning) remains a highly competitive option, especially for scenarios demanding faster response times and cost-efficiency. This detailed Gemini 2.5 Pro Preview (May' 25) vs Gemini 2.5 Flash Preview (Sep '25) (Reasoning) comparison will break down every critical metric to help you make the best decision.

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Model Snapshot

Key decision metrics at a glance.

Gemini 2.5 Pro Preview (May' 25)

Google

Reasoning: 6
Coding: 6
Multimodal: 2
Long Context: 4
Blended Price / 1M tokens: $0.003
P95 Latency: 1000ms
Tokens per second: —

Gemini 2.5 Flash Preview (Sep '25) (Reasoning)

Google

Reasoning: 8
Coding: 2
Multimodal: 3
Long Context: 4
Blended Price / 1M tokens: $0.001
P95 Latency: 1000ms
Tokens per second: 291.224tokens/sec

Overall Capabilities

The capability radar provides a holistic view of the Gemini 2.5 Pro Preview (May' 25) vs Gemini 2.5 Flash Preview (Sep '25) (Reasoning) matchup. This chart illustrates each model's strengths and weaknesses at a glance, forming a cornerstone of our Gemini 2.5 Pro Preview (May' 25) vs Gemini 2.5 Flash Preview (Sep '25) (Reasoning) analysis.

This radar chart visually maps the core capabilities (reasoning, coding, math proxy, multimodal, long context) of `Gemini 2.5 Pro Preview (May' 25)` vs `Gemini 2.5 Flash Preview (Sep '25) (Reasoning)`.

Benchmark Breakdown

For a granular look, this chart directly compares scores across standardized benchmarks. In the critical MMLU Pro test, a key part of the Gemini 2.5 Pro Preview (May' 25) vs Gemini 2.5 Flash Preview (Sep '25) (Reasoning) debate, Gemini 2.5 Pro Preview (May' 25) scores 60 against Gemini 2.5 Flash Preview (Sep '25) (Reasoning)'s 80. This data-driven approach is essential for any serious Gemini 2.5 Pro Preview (May' 25) vs Gemini 2.5 Flash Preview (Sep '25) (Reasoning) comparison.

This grouped bar chart provides a side-by-side comparison for each benchmark metric.

Speed & Latency

Speed is a crucial factor in the Gemini 2.5 Pro Preview (May' 25) vs Gemini 2.5 Flash Preview (Sep '25) (Reasoning) decision for interactive applications. The metrics below highlight the trade-offs you should weigh before shipping to production.

Time to First Token

Gemini 2.5 Pro Preview (May' 25)300ms

Gemini 2.5 Flash Preview (Sep '25) (Reasoning)300ms

Tokens per Second

Gemini 2.5 Pro Preview (May' 25)37

Gemini 2.5 Flash Preview (Sep '25) (Reasoning)291.224

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The Economics of Gemini 2.5 Pro Preview (May' 25) vs Gemini 2.5 Flash Preview (Sep '25) (Reasoning)

Power is only one part of the equation. This Gemini 2.5 Pro Preview (May' 25) vs Gemini 2.5 Flash Preview (Sep '25) (Reasoning) pricing analysis gives you a true sense of value.

Pricing Breakdown

Compare input and output pricing at a glance.

Real-World Cost Scenario

To process 1M input tokens and generate 250k output tokens, Gemini 2.5 Pro Preview (May' 25) would cost $0.004, whereas Gemini 2.5 Flash Preview (Sep '25) (Reasoning) would cost $0.001. This practical calculation is vital for any developer considering the Gemini 2.5 Pro Preview (May' 25) vs Gemini 2.5 Flash Preview (Sep '25) (Reasoning) choice.

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Which Model Wins the Gemini 2.5 Pro Preview (May' 25) vs Gemini 2.5 Flash Preview (Sep '25) (Reasoning) Battle for You?

Choose Gemini 2.5 Pro Preview (May' 25) if...

Cost is a secondary concern to power in your Gemini 2.5 Pro Preview (May' 25) vs Gemini 2.5 Flash Preview (Sep '25) (Reasoning) decision.

You need the most advanced reasoning capabilities available.

Your use case demands cutting-edge AI performance.

Choose Gemini 2.5 Flash Preview (Sep '25) (Reasoning) if...

You need a highly responsive model for user-facing applications.

Your budget is a primary consideration in the Gemini 2.5 Pro Preview (May' 25) vs Gemini 2.5 Flash Preview (Sep '25) (Reasoning) choice.

You are developing at scale where operational costs are critical.

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Your Questions about the Gemini 2.5 Pro Preview (May' 25) vs Gemini 2.5 Flash Preview (Sep '25) (Reasoning) Comparison

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Data source: https://artificialanalysis.ai/