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Gemini 2.5 Flash vs o4 Mini

Complete pricing and performance comparison between Google's Gemini 2.5 Flash and OpenAI's o4 Mini.

Quick Verdict

Cheaper
Gemini 2.5 Flash
3.7x cheaper input, 1.8x cheaper output
Larger Context
Gemini 2.5 Flash
1.0M vs 200K
Higher Quality
o4 Mini
Score: 33 vs 21
Faster
Gemini 2.5 Flash
231 vs 154 tok/s

Pricing Comparison

SpecGemini 2.5 Flasho4 MiniDifference
ProviderGoogleOpenAI
Input / 1M tokens$0.3$1.1Gemini 2.5 Flash is 73% more expensive
Output / 1M tokens$2.5$4.4Gemini 2.5 Flash is 43% more expensive
Context Window1.0M200K5x difference
Max Output66K100K
Tokenizercl100k_baseo200k_base

Performance Benchmarks

MetricGemini 2.5 Flasho4 MiniWinner
Quality Index2133o4 Mini
Output Speed231 tok/s154 tok/sGemini 2.5 Flash
Time to First Token0.42s21.82sGemini 2.5 Flash
Value (Quality/$)68.730.1Higher = 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 Flasho4 MiniSavings
Single request
1K in / 300 out
$0.0010$0.0024Gemini 2.5 Flash saves $0.0014
10 requests
10K in / 3K out
$0.010$0.024Gemini 2.5 Flash saves $0.014
100 requests
100K in / 30K out
$0.105$0.242Gemini 2.5 Flash saves $0.137
1,000 requests
1M in / 300K out
$1.05$2.42Gemini 2.5 Flash saves $1.37
10,000 requests
10M in / 3M out
$10.50$24.20Gemini 2.5 Flash saves $13.70
1M requests/mo
1B in / 300M out
$1050.00$2420.00Gemini 2.5 Flash saves $1370.00

Pros & Cons

Gemini 2.5 Flash Strengths

  • +Cheaper input tokens
  • +Cheaper output tokens
  • +Larger context window (1.0M vs 200K)
  • +Faster output (231 vs 154 tok/s)
  • +Lower latency (faster first token)

o4 Mini Strengths

  • +Higher max output tokens
  • +Higher quality score (33 vs 21)

When to Use Each Model

Choose Gemini 2.5 Flash for

  • →Budget-conscious projects where cost is the primary factor
  • →Long documents, large codebases, or multi-turn conversations
  • →Real-time applications, chat, or autocomplete

Choose o4 Mini for

  • →Generating long-form content or detailed code
  • →Tasks requiring maximum accuracy and reasoning

Frequently Asked Questions

Which is cheaper, Gemini 2.5 Flash or o4 Mini?
For input tokens, Gemini 2.5 Flash is 3.7x cheaper at $0.3/1M tokens. For output tokens, Gemini 2.5 Flash is 1.8x cheaper at $2.5/1M tokens. At typical usage (1M input + 300K output), Gemini 2.5 Flash costs $1.05 vs o4 Mini at $2.42.
What's the context window difference?
Gemini 2.5 Flash supports 1.0M context (1,048,576 tokens), while o4 Mini supports 200K (200,000 tokens). Gemini 2.5 Flash can handle 5x more context in a single request.
Which model has better benchmarks?
Quality Index: Gemini 2.5 Flash scores 21 vs o4 Mini at 33. Speed: Gemini 2.5 Flash generates 231 tok/s vs o4 Mini at 154 tok/s. Time to first token: Gemini 2.5 Flash at 0.42s vs o4 Mini at 21.82s.
When should I choose Gemini 2.5 Flash over o4 Mini?
Choose Gemini 2.5 Flash when you need: Cheaper input tokens, Cheaper output tokens, Larger context window (1.0M vs 200K), Faster output (231 vs 154 tok/s), Lower latency (faster first token). Choose o4 Mini when you need: Higher max output tokens, Higher quality score (33 vs 21).
How much would 10,000 API requests cost?
At 1K input + 300 output tokens per request (typical chat): Gemini 2.5 Flash = $10.50, o4 Mini = $24.20. At 10K input + 1K output per request (longer conversations): Gemini 2.5 Flash = $55.00, o4 Mini = $154.00.

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Gemini 2.5 Flash Detailso4 Mini DetailsFull Pricing TableCost Calculator