Which model is better: Gemini 2.5 Flash or Gemini 3.5 Flash-Lite?
Gemini 3.5 Flash-Lite is 75.0% cheaper for input tokens ($0.07 vs. $0.30 per 1M tokens) and $0.30 vs. $2.50 for output tokens (4.0x cost advantage). In terms of operational performance, Gemini 3.5 Flash-Lite delivers lower response latency at 78ms TTFT (32ms faster than Gemini 2.5 Flash) with 265 vs. 180 tok/s throughput. Gemini 2.5 Flash leads coding evaluations at 58.0% SWE-bench Verified vs. 55.4% for Gemini 3.5 Flash-Lite and 70.5% vs. 68.4% on GPQA Diamond.
Verified daily via automated API latency tests and official documentation.
Zero-Shot RAG Verified
Verified Performance & Unit Economics Delta (12 Dimensions)
Daily synchronized metrics across token pricing, prompt cache economics, latency, throughput, and 5 capability benchmarks.
Metric / Dimension
Gemini 2.5 Flash
Gemini 3.5 Flash-Lite
Net Delta / Advantage
Input Cost / 1M Tokens
$0.30
$0.07
Gemini 3.5 Flash-Lite is 4.0x cheaper
Output Cost / 1M Tokens
$2.50
$0.30
Gemini 3.5 Flash-Lite (88.0% lower)
Prompt Cache Read / 1M
$0.030
$0.015
Gemini 3.5 Flash-Lite is 2.0x cheaper
Prompt Cache Write / 1M
$0.30
$0.07
Gemini 3.5 Flash-Lite is 4.0x cheaper
Context Window (Max Output)
1,049k (66k out)
1,049k (33k out)
Equal Context Window
Avg TTFT Response Latency
110ms
78ms
Gemini 3.5 Flash-Lite (32ms faster)
Generation Speed (Throughput)
180 tok/s
265 tok/s
Gemini 3.5 Flash-Lite (+85 tok/s faster)
SWE-bench Verified (Coding)
58%
55.4%
Gemini 2.5 Flash (+2.6% lead)
GPQA Diamond (PhD STEM)
70.5%
68.4%
Gemini 2.5 Flash (+2.1% lead)
MMLU-Pro (Multi-Discipline)
82%
80.1%
Gemini 2.5 Flash (+1.9% lead)
MATH-500 (Quantitative Logic)
89%
90.2%
Gemini 3.5 Flash-Lite (+1.2% lead)
Inference Value Score (IVR)
66.6 / 100
81.5 / 100
Gemini 3.5 Flash-Lite (+14.9 pts)
Interactive Monthly Token Economics & ROI Forecaster
Model production workloads across prompt, completion, and cached context tokens, or switch models on the fly.
Which is cheaper: Gemini 2.5 Flash or Gemini 3.5 Flash-Lite?
Gemini 3.5 Flash-Lite is cheaper at $0.075/1M input tokens ($0.30/1M output) compared to $0.30/1M input ($2.50/1M output) for Gemini 2.5 Flash.
Which model has lower TTFT latency and higher tok/s throughput: Gemini 2.5 Flash or Gemini 3.5 Flash-Lite?
Gemini 3.5 Flash-Lite delivers faster first-token latency at 78ms TTFT (265 tok/s throughput) compared to 110ms TTFT (180 tok/s) for Gemini 2.5 Flash.
How do Gemini 2.5 Flash and Gemini 3.5 Flash-Lite compare on SWE-bench coding and GPQA Diamond reasoning?
On SWE-bench Verified software engineering, Gemini 2.5 Flash scores 58% versus 55.4% for Gemini 3.5 Flash-Lite. On GPQA Diamond graduate-level STEM reasoning, Gemini 2.5 Flash scores 70.5% versus 68.4% for Gemini 3.5 Flash-Lite (and 89% vs 90.2% on MATH-500).
When should you choose Gemini 2.5 Flash?
Choose Gemini 2.5 Flash (Google) for cost-efficient 1M-context summarization, multimodal extraction, and interactive assistants — offering a 1,048k context window, 110ms TTFT, and $0.30/1M input pricing ($0.030/1M cached reads).
When should you choose Gemini 3.5 Flash-Lite?
Choose Gemini 3.5 Flash-Lite (Google) for high-frequency data pipelines, real-time routing, large-scale document tagging, and ultra-low-cost conversational assistants — offering a 1,048k context window, 78ms TTFT, and $0.07/1M input pricing ($0.015/1M cached reads).
