Compare/Gemini 3 Flash Preview (Reasoning) vs Gemini 2.5 Pro Preview (May' 25)

Gemini 3 Flash Preview (Reasoning)vsGemini 2.5 Pro Preview (May' 25)

Side-by-side comparison of pricing, 12 benchmarks, and generation speed.

Google

Gemini 3 Flash Preview (Reasoning)

Input
$0.5/M
Output
$3/M
Speed
180 tok/s
TTFT
6.33s
Google

Gemini 2.5 Pro Preview (May' 25)

Input
$1.25/M
Output
$10/M
Speed
TTFT

Winner by Category

Cheaper
Gemini 3 Flash Preview (Reasoning)
Faster (tok/s)
Gemini 3 Flash Preview (Reasoning)
Lower Latency
Gemini 2.5 Pro Preview (May' 25)
Benchmarks (11-1)
Gemini 3 Flash Preview (Reasoning)

Pricing Comparison

MetricGemini 3 Flash Preview (Reasoning)Gemini 2.5 Pro Preview (May' 25)
Input ($/M tokens)$0.5$1.25
Output ($/M tokens)$3$10
Cost for 1M input + 100K output tokens:
Gemini 3 Flash Preview (Reasoning)$0.80
Gemini 2.5 Pro Preview (May' 25)$2.25

Speed Comparison

Output Speed (tokens/s) — higher is better
Gemini 3 Flash Preview (Reasoning)
180 tok/s
Gemini 2.5 Pro Preview (May' 25)
Time to First Token (seconds) — lower is better
Gemini 3 Flash Preview (Reasoning)
6.33s
Gemini 2.5 Pro Preview (May' 25)

Benchmark Comparison

Data from Artificial Analysis API — 12 benchmarks

Intelligence Index
46.429.5
Coding Index
42.6
Math Index
97.0
GPQA Diamond
89.8%82.2%
MMLU-Pro
89.0%83.7%
LiveCodeBench
90.8%77.0%
AIME 2025
97.0%
MATH-500
98.6%
Humanity's Last Exam
34.7%15.4%
SciCode
50.6%41.6%
IFBench
78.0%
TerminalBench
38.6%
Gemini 3 Flash Preview (Reasoning)11 wins
1 winsGemini 2.5 Pro Preview (May' 25)

Frequently Asked Questions

Which is cheaper, Gemini 3 Flash Preview (Reasoning) or Gemini 2.5 Pro Preview (May' 25)?

Gemini 3 Flash Preview (Reasoning) is cheaper overall. Its blended price (3:1 input/output ratio) is $1.13/M tokens vs $3.44/M for Gemini 2.5 Pro Preview (May' 25).

Which model performs better on benchmarks?

Gemini 3 Flash Preview (Reasoning) wins 11 out of 12 benchmarks compared to 1 for Gemini 2.5 Pro Preview (May' 25). See the detailed benchmark chart above for per-category results.

Which is faster for real-time applications?

Gemini 3 Flash Preview (Reasoning) generates tokens faster at 180 tok/s vs 0 tok/s. However, Gemini 2.5 Pro Preview (May' 25) has lower time-to-first-token (0.00s vs 6.33s).

When should I use Gemini 3 Flash Preview (Reasoning) vs Gemini 2.5 Pro Preview (May' 25)?

Choose based on your priorities: Gemini 3 Flash Preview (Reasoning) for lower cost, Gemini 3 Flash Preview (Reasoning) for stronger benchmark performance, and Gemini 3 Flash Preview (Reasoning) for faster generation. For latency-sensitive apps, check the TTFT comparison above.