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Gemini 2.5 Flash-Lite vs Gemini 3.1 Flash-Lite

Complete pricing and performance comparison between Google's Gemini 2.5 Flash-Lite and Google's Gemini 3.1 Flash-Lite.

Quick Verdict

Cheaper
Gemini 2.5 Flash-Lite
2.5x cheaper input, 3.8x cheaper output
Larger Context
Gemini 2.5 Flash-Lite
1.0M vs 1.0M
Higher Quality
Gemini 3.1 Flash-Lite
Score: 34 vs 13
Faster
Gemini 2.5 Flash-Lite
336 vs 219 tok/s

Pricing Comparison

SpecGemini 2.5 Flash-LiteGemini 3.1 Flash-LiteDifference
ProviderGoogleGoogle
Input / 1M tokens$0.1$0.25Gemini 2.5 Flash-Lite is 60% more expensive
Output / 1M tokens$0.4$1.5Gemini 2.5 Flash-Lite is 73% more expensive
Context Window1.0M1.0MSame
Max Output66K66K

Performance Benchmarks

MetricGemini 2.5 Flash-LiteGemini 3.1 Flash-LiteWinner
Quality Index1334Gemini 3.1 Flash-Lite
Output Speed336 tok/s219 tok/sGemini 2.5 Flash-Lite
Time to First Token0.27s7.76sGemini 2.5 Flash-Lite
Value (Quality/$)127.0134.0Higher = better value

Benchmark data from Artificial Analysis. Quality Index is a composite score across reasoning, coding, and knowledge tasks.

Cost at Scale

Estimated cost at different usage levels (3:1 input-to-output token ratio, typical for chat).

UsageGemini 2.5 Flash-LiteGemini 3.1 Flash-LiteSavings
Single request
1K in / 300 out
$0.0002$0.0007Same
10 requests
10K in / 3K out
$0.0022$0.0070Gemini 2.5 Flash-Lite saves $0.0048
100 requests
100K in / 30K out
$0.022$0.070Gemini 2.5 Flash-Lite saves $0.048
1,000 requests
1M in / 300K out
$0.220$0.700Gemini 2.5 Flash-Lite saves $0.480
10,000 requests
10M in / 3M out
$2.20$7.00Gemini 2.5 Flash-Lite saves $4.80
1M requests/mo
1B in / 300M out
$220.00$700.00Gemini 2.5 Flash-Lite saves $480.00

Pros & Cons

Gemini 2.5 Flash-Lite Strengths

  • +Cheaper input tokens
  • +Cheaper output tokens
  • +Faster output (336 vs 219 tok/s)
  • +Lower latency (faster first token)

Gemini 3.1 Flash-Lite Strengths

  • +Higher quality score (34 vs 13)

When to Use Each Model

Choose Gemini 2.5 Flash-Lite for

  • →Budget-conscious projects where cost is the primary factor
  • →Real-time applications, chat, or autocomplete

Choose Gemini 3.1 Flash-Lite for

  • →Tasks requiring maximum accuracy and reasoning

Frequently Asked Questions

Which is cheaper, Gemini 2.5 Flash-Lite or Gemini 3.1 Flash-Lite?
For input tokens, Gemini 2.5 Flash-Lite is 2.5x cheaper at $0.1/1M tokens. For output tokens, Gemini 2.5 Flash-Lite is 3.8x cheaper at $0.4/1M tokens. At typical usage (1M input + 300K output), Gemini 2.5 Flash-Lite costs $0.220 vs Gemini 3.1 Flash-Lite at $0.700.
What's the context window difference?
Gemini 2.5 Flash-Lite supports 1.0M context (1,048,576 tokens), while Gemini 3.1 Flash-Lite supports 1.0M (1,048,576 tokens). Gemini 3.1 Flash-Lite can handle 1x more context in a single request.
Which model has better benchmarks?
Quality Index: Gemini 2.5 Flash-Lite scores 13 vs Gemini 3.1 Flash-Lite at 34. Speed: Gemini 2.5 Flash-Lite generates 336 tok/s vs Gemini 3.1 Flash-Lite at 219 tok/s. Time to first token: Gemini 2.5 Flash-Lite at 0.27s vs Gemini 3.1 Flash-Lite at 7.76s.
When should I choose Gemini 2.5 Flash-Lite over Gemini 3.1 Flash-Lite?
Choose Gemini 2.5 Flash-Lite when you need: Cheaper input tokens, Cheaper output tokens, Faster output (336 vs 219 tok/s), Lower latency (faster first token). Choose Gemini 3.1 Flash-Lite when you need: Higher quality score (34 vs 13).
How much would 10,000 API requests cost?
At 1K input + 300 output tokens per request (typical chat): Gemini 2.5 Flash-Lite = $2.20, Gemini 3.1 Flash-Lite = $7.00. At 10K input + 1K output per request (longer conversations): Gemini 2.5 Flash-Lite = $14.00, Gemini 3.1 Flash-Lite = $40.00.

Related Comparisons

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Gemini 3.1 Flash-Lite vs GPT-5.4 Mini
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Gemini 3.1 Flash-Lite vs GPT-5.4 Nano
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Gemini 2.5 Flash-Lite DetailsGemini 3.1 Flash-Lite DetailsFull Pricing TableCost Calculator